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Electrical properties and microstructure of phosphorus (P) implanted p-type Si substrates were evaluated by four-point probe (4PP), Differential Hall Effect Metrology (DHEM), secondary ion mass spectrometry (SIMS) and transmission electron microscopy (TEM) techniques, after RTA 750–950°C and CO2 laser 120–140W annealing. When RTA temperature was increased, defect concentration at a-Si/c-Si interface gradually disappeared. For CO2 laser annealing, defects were found to aggregate at the end of range (EOR) region. Sheet resistance (Rs) values decreased significantly with increasing RTA temperature due to defects disappearing at EOR. Rs did not change appreciably for the CO2 laser annealing case. The dopant activation ratio was less than 50% below RTA temperature of 850 °C, and it increased to 70% at 950 °C. For CO2 laser annealing, the activation ratio could reach to over 80% regardless of the laser power. The highest active concentration and the lowest resistivity or mobility were found to be within the top 20 nm region of the surface. Although RTA annealing conditions influenced dopant diffusion and the resulting electrical property depth profiles significantly, depth profiles did not change much with changes in CO2 laser power level. It was demonstrated that DHEM data in conjunction with SIMS and TEM data can be successfully employed to evaluate, in detail, the electrical properties of ultra-shallow junctions for metal oxide semiconductor field effect transistor (MOSFET) applications.

A process for activating Mg and its relationship with vacancy-type defects in Mg-implanted GaN were studied by positron annihilation spectroscopy. Mg+ ions were implanted with an energy of 10 keV, and the Mg concentration in the subsurface region (≤ 50 nm) was on the order of 1019 cm−3. After the Mg-implantation, N+ ions were implanted to provide a 300-nm-deep box profile with a N concentration of 6 × 1018 cm−3. From capacitance–voltage measurements, the sequential implantation of N was found to enhance the activation of Mg. For N-implanted GaN before annealing, the major defect species were determined to Ga-vacancy related defects such as divacancy. After annealing below 1000 °C, the clustering of vacancies was observed. Above 1200 °C annealing, however, the size of the vacancies started to decrease, which was due to recombinations of vacancy clusters and excess N atoms in the damaged region. The suppression of vacancy clustering by sequential N-implantation in Mg-implanted GaN was attributed to the origin of the enhancement of the Mg activation.

In-situ doping of CdTe/CdSeTe films with arsenic is performed using pre-doped source material prepared by high pressure Bridgman (HPB) melt growth. Arsenic level in the source material is varied from 1018-1020 cm−3. Correspondingly, dopant incorporation in the films prepared using vapor transport deposition (VTD) varied from 3×1017 cm−3-1×1018cm−3. In this range, dopant activation is found to inversely correlate with the dopant incorporation, suggesting compensation. The results from this study indicate film properties can be adjusted by source material.

Positron annihilation spectroscopy in the Doppler and coincidence Doppler mode was applied on Ge 1 − xSn x epitaxial layers, grown by chemical vapor deposition with different total As concentrations ( ∼ 10 19– 10 21 cm − 3), high active As concentrations ( ∼ 10 19 cm − 3), and similar Sn concentrations (5.9%–6.4%). Positron traps are identified as mono-vacancy complexes. Vacancy-As complexes, V-As i, formed during the growth were studied to deepen the understanding of the electrical passivation of the Ge 1 − xSn x:As epilayers. Larger mono-vacancy complexes, V-As i ( i ≥ 2), are formed as the As doping increases. The total As concentration shows a significant impact on the saturation of the number of As atoms ( i = 4) around the vacancies in the sample epilayers. The presence of V-As i complexes decreases the dopant activation in the Ge 1 − xSn x:As epilayers. Furthermore, the presence of Sn failed to hinder the formation of larger V-As i complexes and thus failed to reduce the donor-deactivation.

First-principles calculations are used to systematically investigate the impact of surface effects on the energetic cost to incorporate point defects near the growing surface [Ge(001)] and its consequence on the dopant activation in P-doped Ge layers. We illustrate the formation enthalpy Delta H-f for the incorporation of a mono-vacancy, which is the dominant point defect responsible for the electrically inactive dopant incorporation in P-doped Ge. The calculated values point toward a significant lowering of Delta H-f near the growing surface in comparison to the bulk cubic Ge supercell. The impact of the surface almost vanishes beyond the sixth atomic monolayer located below the surface and the calculated Delta H-f values overlap with the ones computed for a bulk cubic Ge supercell. For epitaxial Ge:P layers, grown at low growth temperatures (

Iodine-doped CdTe and Cd1−x Mg x Te layers were grown by molecular beam epitaxy. Secondary ion mass spectrometry characterization was used to measure dopant concentration, while Hall measurement was used for determining carrier concentration. Photoluminescence intensity and time-resolved photoluminescence techniques were used for optical characterization. Maximum n-type carrier concentrations of 7.4 × 1018 cm−3 for CdTe and 3 × 1017 cm−3 for Cd0.65Mg0.35Te were achieved. Studies suggest that electrically active doping with iodine is limited with dopant concentration much above these values. Dopant activation of about 80% was observed in most of the CdTe samples. The estimated activation energy is about 6 meV for CdTe and the value for Cd0.65Mg0.35Te is about 58 meV. Iodine-doped samples exhibit long lifetimes with no evidence of photoluminescence degradation with doping as high as 2 × 1018 cm−3, while indium shows substantial non-radiative recombination at carrier concentrations above 5 × 1016 cm−3. Iodine was shown to be thermally stable in CdTe at temperatures up to 600°C. Results suggest iodine may be a preferred n-type dopant compared to indium in achieving heavily doped n-type CdTe.

This work describes the development of a new method for ion implantation induced crystal damage recovery using multiple XeCl (308 nm) laser pulses with a duration of 30 ns. Experimental activity was carried on single phosphorus (P) as well as double phosphorus and aluminum (Al) implanted 4H-SiC epitaxial layers. Samples were then characterized through micro-Raman spectroscopy, Photoluminescence (PL) and Transmission Electron Microscopy (TEM) and results were compared with those coming from P implanted thermally annealed samples at 1650&ndash, 1700&ndash, 1750 &deg, C for 1 h as well as P and Al implanted samples annealed at 1650 &deg, C for 30 min. The activity outcome shows that laser annealing allows to achieve full crystal recovery in the energy density range between 0.50 and 0.60 J/cm2. Moreover, laser treated crystal shows an almost stress-free lattice with respect to thermally annealed samples that are characterized by high point and extended defects concentration. Laser annealing process, instead, allows to strongly reduce carbon vacancy (VC) concentration in the implanted area and to avoid intra-bandgap carrier recombination centres. Implanted area was almost preserved, except for some surface oxidation processes due to oxygen leakage inside the testing chamber. However, the results of this experimental activity gives way to laser annealing process viability for damage recovery and dopant activation inside the implanted area.

Copper-free polycrystalline CdTe solar cells doped with either Phosphorus, Arsenic or Antimony are compared for dopability, device performance and defect properties. In-situ doping of CdTe with group-V elements was carried out using vapor transport deposition followed by CdCl2 heat treatment. Uniform carrier concentration in ~1016 cm-3 range is achieved for all three dopants. Compatibility with CdSeTe ternary alloy is demonstrated and comparable quantum efficiency for all three dopants suggests that either dopant could serve as a replacement for copper. These results are compared with previously reported carrier concentration values for group-V doping of sx- and px- CdTe. Theoretical calculation for maximum carrier concentration based on acceptor energy level suggests least ionization of Antimony. Compensation worsens the achievable majority carrier concentration despite high acceptor doping.

The record low contact resistivity $(\rho_{\text{c}})$ of $4.4\text{x}10^{-10}\Omega-\text{cm}^{2}$ is achieved in Ti metal contact to in-situ B-doped $\text{GeSn}$ using B $(> 1\text{x}10^{21}\text{cm}^{-3})$ and Sn $(> 12\%)$ segregations at the Ti/GeSn:B interface. Sn incorporation into Ge lowers the Schottky barrier height of holes. Increasing B doping at the $\text{Ti}/\text{GeSn}:\text{B}$ interface reduces the hole tunneling distance. Thanks to the low growth temperature (305°C) of the chemical vapor deposition using Ge2H6, the GeSn:B with the bulk active [B] of $2.1\text{x}10^{20}\text{cm}^{-3} (>> > \text{the}$ solid solubility of B in $\text{Ge}=5.5\text{x}10^{18}\text{cm}^{-3}$ ) and the bulk [Sn] of 4.9% is successfully grown. Without the needs of the previously reported Ga dopants and the high temperature annealing for dopant activation, the record low $\rho_{\text{c}}$ is achieved with all the process temperatures $\leq 400^{\text{o}}\text{C}$ .

In this paper, we report on the phase selectivity in Cr and N co-doped TiO2 (TiO2:Cr,N) sputtered films by means of interface engineering. In particular, monolithic TiO2:Cr,N films produced by continuous growth conditions result in the formation of a mixed-phase oxide with dominant rutile character. On the contrary, modulated growth by starting with a single-phase anatase TiO2:N buffer layer, can be used to imprint the anatase structure to a subsequent TiO2:Cr,N layer. The robustness of the process with respect to the growth conditions has also been investigated, especially regarding the maximum Cr content (, The research leading to these results has received funding from projects RTI2018-095137-B-I00 and MAT2016-80394-R from Ministerio de Ciencia, Innovación y Universidades (Spain) and grant agreement n° 226716 from the European Community’s Seventh Framework Programme (FP7/2007-2013). Funding of TEM Talos F200X by the German Federal Ministry of Education of Research (BMBF) through Grant No. 03SF0451 in the framework of HEMCP is gratefully acknowledged.

Germanium n+/p junctions with high phosphorus dopant activation (>1020 cm−3) and minimal dopant diffusion were achieved by $P$ implantation and laser spike annealing (LSA) at temperatures ≥794 °C for 400 $\mu \text{s}$ . In addition, there is no evidence of any residual extended defectivity near the junction after LSA. The effect of F co-doping was also investigated, demonstrating the reduction in both diffusion and activation. The thermal stability and electrical characteristics of Ge n+/p junction activated by LSA were evaluated.

In this study, the application of atmospheric pressure thermal plasma jet (TPJ) annealing for impurity activation in 4H–SiC is reported. The activation of phosphorus atoms implanted at 300°C in 4H–SiC by TPJ irradiation and analysis of its crystallinity are investigated. At the maximum annealing temperature of 1630°C, the minimum resistivity value is 3.1 mΩ·cm and the maximum carrier concentration value is 2.0 × 1020 cm−3. Orientation analysis suggests that the sample implanted at 300°C was recrystallized to a 4H–SiC(0001) structure after 1630°C annealing. Furthermore, a significant increase in the carrier concentration was observed with the increasing cooling rate during the activation annealing process. Rapid cooling may suppress the impurity deactivation. These results suggest that short-time high-temperature TPJ irradiation annealing is effective for P dopant activation in 4H–SiC.

In this paper, we report on the characterization of Si thin films doped by wet-chemical laser processing. Using this method, implantation and dopant activation can be performed simultaneously. After laser doping, the mobility, carrier concentration, and resistivity of the films were 74 cm2/V·s, 5.5 × 1017 cm−3, and 0.15 Ω·cm, respectively.

Ion implantation of the amphoteric dopant Si compared to the natural n-type dopant S in GaSb epitaxial films results in a higher dopant activation with better surface morphology and crystallinity. GaSb films were grown by molecular beam epitaxy (MBE) on semi-insulating GaAs (001) substrates. Ion implantation for both ions was carried out at an energy of 50 keV and a fluence of 1 × 1015 ions/cm2. Raman spectroscopy revealed a better crystallinity as well as a lower Sb out-diffusion for Si implantation as compared to S after annealing. Van der Pauw Hall measurements confirm the donor nature of the amphoteric dopant Si and with a dopant activation that is 3 times higher than the natural donor S. The electrical activation for both implants increases significantly after thermal annealing. Using temperature (20 K–300 K) vs conductivity measurement and displacement per atom (dpa) estimation, implantation-induced defect-related conduction mechanism is discussed. The results suggest the scope of Si as a viable n-type dopant in GaSb.

In this study, two-step, low energy (2 keV + 1 keV) ion implantation and low-temperature microwave annealing (MWA) were employed to recover and activate boron implanted SiGe wafers. The boron was introduced by a combination of in situ doping during epi-growth (3.2 × 1020 cm−3) and a two-step ion implantation process (3 × 1015 cm−2 and 2 × 1015 cm−2). The activation of boron, which is close to the solid solubility limit in SiGe, was investigated following MWA or rapid thermal annealing. The thermal process was found to have the dominant effect on activation, but the SiGe composition also had an effect. For Ge content between 20% and 40%, Si 0.65 Ge 0.35 is an optimum alloy. Following implantation and annealing, boron distribution, sheet resistance, and mobility were checked to infer the activation level and defect evolution. A pre-amorphization implant using Ge ions has the best performance, and can effectively enhance the boron activation while preventing diffusion, when followed by MWA.

Ion decoupled plasma technique with low ion energy have been used to demonstrate conformal shallow junctions of phosphorous with higher than l E20 of dopants for germanium (Ge). Adding antimony (Sb) in plasma-assisted doping was found to enhance the phosphorous (P) dopant level dramatically. Various annealing techniques were compared to understand the impact to dopant activation and levels to form shallow junctions with enhanced P level.

Arsenic dopant was incorporated in CdTe absorber layers in high-efficiency CdTe cells using feedstock doped with 1018cc-1for sublimation of films. The goal of the work was to develop a feasible method for creating a hole density equal to, or greater than that currently achievable using copper doping using a CuCl treatment. Doping with arsenic resulted in a modest increase in open-circuit voltage (V OC ) and a large improvement in fill-factor and conversion efficiency when compared with copper-doped devices with similar structure. All experiments were performed in the presence of cadmium overpressure to encourage dopant activation in tellurium vacancy sites. Arsenic incorporation was measured using Secondary Ion Mass Spectrometry (SIMS) at 4E +16 atoms/cc-1,about four times greater incorporation than previously seen by the authors. Using a CdSeTe/CdTe graded absorber and arsenic doping, a conversion efficiency of 16.79% was achieved.

Advanced inductively coupled plasma and atomic layer deposition (ALD) techniques with low ion energy have been used to demonstrate conformal shallow junctions of phosphorous with higher than 1E20 of dopants for germanium (Ge). Adding antimony (Sb) in both plasma-assisted and ALD doping was found to enhance the phosphorous (P) dopant level dramatically. Various annealing techniques were compared to understand the impact to dopant activation and levels to form shallow junctions with enhanced P level.

In this study, the application of atmospheric pressure thermal plasma jet (TPJ) annealing for impurity activation in 4H-SiC is reported. The activation of phosphorus atoms implanted at 300°C in 4H-SiC by TPJ irradiation and analysis of its crystallinity are investigated. At the maximum annealing temperature of 1630°C, the minimum resistivity value is 3.1 mΩ·cm and the maximum free electron concentration value is 2.0 χ 1020 cm−3. Crystal orientation analysis suggests that the sample implanted at 300°C was recrystallized to a 4H-SiC(0001) structure after 1630°C annealing. Furthermore, a significant increase in the carrier concentration was observed with the increasing cooling rate during the activation annealing process. Rapid cooling may suppress the impurity deactivation. These results suggest that short-time high-temperature TPJ irradiation annealing is effective for P dopant activation in 4H-SiC.

High band gap (3.34 eV) and large exciton binding energy (60 meV) at room temperature facilitates ZnO as a useful candidate for optoelectronics devices. Presence of zinc interstitial and oxygen vacancies results in n-type ZnO film. Phosphorus implantation was carried out using plasma immersion ion implantation technique (2kV, 900W) for constant duration (50 s) on RF sputtered ZnO thin films (Sample A). For dopant activation, sample A was subjected to Rapid Thermal Annealing (RTA) at 700, 800, 900 and 1000°C for 10 s in Oxygen ambient (Sample B, C, D, E). Low temperature (18 K) photoluminescence measurement demonstrated strong donor bound exciton peak for sample A. Dominant donor to acceptor pair peak (DAP) was observed for sample D at around 3.22 eV with linewidth of 131.3 meV. High resolution x-ray diffraction measurement demonstrated (001) and (002) peaks for sample A. (002) peak with high intensity was observed from all annealed samples. Incorporation of phosphorus in ZnO films leads to peak shift towards higher 2θ angle indicate tensile strain in implanted samples. Scanning electron microscopy images reveals improvement in grain size distribution along with reduction of implantation related defects. Raman spectra measured A1(LO) peak at around 576 cm -1 for sample A. Low intensity E2 (high) peak was observed for sample D indicating formation of (P Zn +2V Zn ) complexes. From room temperature Hall measurement, sample D measured 1.17 x 10 18 cm -3 carrier concentration with low resistivity of 0.464 Ω.

In this paper, we present a detailed study of temperature-based ion implantation of phosphorus dopants in Ge for varying dose and anneal conditions through fabricated n+/p junctions and n-type MOSFETs (nMOSFETs). In comparison with room temperature (RT) (25 °C) and hot (400 °C) implantation, cryogenic (−100 °C) implantation with a dose of 2.2e15 $\mathrm{cm}^{-2}$ followed by a (400 °C) rapid thermal annealing leads to 1) lower junction leakage with higher activation energy and 2) lower sheet resistance with higher dopant activation and shallower junction depth. Gate-last Ge nMOSFETs fabricated using cryogenic implanted n+/p source/drain junction (2.2e15 $\mathrm{cm}^{-2}$ ) exhibit lower off-current (upto $5\times )$ and higher ON-current compared with RT (25 °C) and hot (400 °C) implanted nMOSFETs. This paper demonstrates that cryogenic implantation (−100 °C) can enable high-performance Ge nMOSFETs by alleviating the problems of lower activation and high diffusion of phosphorus in Ge.

In this paper, we report on super low temperature doping of phosphorus to poly-Si thin films using XeF excimer laser irradiation in a phosphoric acid solution. In this method, the implantation of P atoms and dopant activation can be performed simultaneously. We prepared poly-Si films with a thickness of 50 nm, and these films were crystallized using XeF excimer laser annealing. After laser doping, the concentration of P atoms in the poly-Si films was approximately 3.5 × 1018 cm−3, and the resistance of the poly-Si films decreased by approximately 0.003 times as compared with that before laser doping.

We propose an empirical model to accurately predict electrical activation ratios of phosphorus and nitrogen implanted silicon carbide for arbitrary annealing temperatures. We introduce model parameters and compare the activation behaviour of the two donor-type dopants. Our investigations show that the activation ratio of the nitrogen implanted silicon carbide is similar to a step function, while the activation ratio for the phosphorus implanted silicon carbide increases continuously with post-implantation annealing temperature. The model has been implemented into Silvaco's Victory Process simulator, which has enabled accurate predictions of dopant activation in postimplantation steps for silicon carbide-based processes. Several simulations have been performed to extract the depth profiles of the active dopant concentrations and to predict the activation as a function of total doping concentration and annealing temperature.

Low contact resistance (Rc) is key to boost device performance for sub-10nm node. At VLSI Technology Symposium 2016 Samsung reported they reduced Rc by 10% from 14nm to 10nm bulk FinFET technology [1]. TSMC in their beyond 10nm node FinFET paper reported reducing S/D (source/drain) parasitic resistance and enhanced contact process [2] and at IEDM-2016 reported 7nm FinFET reduced S/D parasitic resistance and developed a novel contact process [3]. A complete session #7 was dedicated to “Contact Resistance Innovations for Sub 10nm Scaling” with 4 papers at the VLSI Technology Symposium 2016 [4-7]. To achieve Rc in the low E-9 Ωcm2 requires active dopant carrier concentration >5E20/cm3 to low E21/cm3. For SiP n+ S/D contacts P >1E21/cm3 active dopant carrier concentration is realized with laser melt annealing resulting in Rc

International audience; In this work, we investigate the impact of growth parameters on surface morphology, doping levels and dopant activation in AlGaP epilayers grown on GaP substrate by solid source molecular beam epitaxy. Atomic Force Microscopy analysis reveals that a smooth surface can be obtained only in the [580– 680] °C growth temperature range for a sufficiently large V/III ratio. From C(V), Hall measurements and SIMS analysis, it is shown that a reasonable activated p-doping (Be) value (typically 10e18 cm-3) can be reached if the growth temperature remains larger than 580 °C. For the n-doping (Si), the situation is much more critical, as a growth temperature below 650 °C leads to a strongly insulating layer. This dopant activation issue is related to the appearance of deep traps that are generated when growth temperature is not high enough, as evidenced by deep level transient spectroscopy and isothermal deep level transient spectroscopy. It is therefore suggested that electrically-driven devices using AlGaP epilayers have to be carefully designed in order to match both roughness and dopants activation constraints on growth temperatures and growth rates.

Radio-frequency (RF) hydrogen plasma treatment, thermal annealing in a furnace, and rapid thermal annealing of high-dose P+ ion implanted p-type Ge layers have been studied by Raman scattering spectroscopy, atomic force microscopy, secondary ion mass spectrometry, electrochemical capacitance–voltage profiling, four-point probes method, and x-ray reflectometry. It was shown that low-temperature RF plasma treatment at temperature about 200 °C resulted in full recrystallization of amorphous Ge layer implanted by P+ ions and activation of implanted impurity up to 6.5 × 1019 cm−3 with a maximum concentration at the depth of about 20 nm. Rapid thermal annealing (15 s) and thermal annealing (10 min) in nitrogen ambient required considerably higher temperatures for the recrystallization and activation processes that resulted in diffusion of implanted impurity inside the Ge bulk. It was demonstrated that RF plasma treatment from the samples with front (implanted) side resulted in considerable stronger effects of r...

We report on the application of laser chemical processing (LCP) to fabricate n-type emitters for polysilicon thin-film solar cells on glass. Sheet resistance values of 2-5 kΩ/□ with a peak phosphorus doping concentration in the range 8 × 10 18 -1 × 10 19 cm -3 at a shallow doping depth of less than 350 nm are achieved. After dopant activation and a hydrogenation process, the best cell has an average V oc of (446 ± 7) mV and a pseudofill factor (pFF) of (68.3 ± 0.9)%. This paper demonstrates that LCP can be successfully applied to fabricate an active layer for polysilicon thin-film solar cells on glass. Further improvement in the V oc and the pFF may be possible by optimizing the post-LCP annealing and hydrogenation process, as well as using a poly-Si film of superior material quality.

Highly-conductive B-doped nc-Si:H was deposited at room temperature by using electron cyclotron resonance (ECR) plasma enhanced chemical vapor deposition (PECVD) with a slot antenna (SLAN ECR-PECVD) for low-temperature-process solar-cell and thin-film-transistor (TFT) applications. A novel SLAN ECR plasma source has a higher ionization rate compared to a RF plasma source, with a plasma density of ~1011 cm−3 at 1 mTorr. Spectroscopic ellipsometry, I–V, Raman spectroscopy, and UV-Vis spectroscopy measurements were used for the characterization. B-doped a-Si:H deposited at low H2 flow rates ( 30 sccm), it becomes highly conductive, 0.9–1.7 S/cm. The dopant activation energy is very low at 0.028 eV in spite of the room-temperature deposition. At 40 sccm of H2, the crystalline volume fraction of the film becomes 65%, and the crystal size is around 9.26 nm. Both the crystallinity and the crystal size increase with increasing flow of H2 and enable dopant activation. The optical bandgap varies from 2.07 to 2.35 eV with increasing H2 flow, and the film is useful as a wide-bandgap p-layer for use in p-i-n solar cells or for low-temperature-process TFT applications.

Laser Thermal Processing (LTP) both at silicon melting and sub-melting powers have been studied for many years in order to achieve high levels of dopant activation and abrupt junctions thanks to extremely short annealing times with potential elimination of transient-enhanced diffusion. However, its introduction in a CMOS-like process is not achieved yet, since the laser energy can be destructive to other parts of the device, integration issues related to the introduction of effective reflecting layers to protect devices from laser have not been solved yet. In the present work we present a preliminary characterization in order to identify the most promising implantations and LTP process for both standard and emerging device. Both melting and sub-melting regime was investigated. A first characterization by transmission electron microscopy (TEM), time of flight secondary ion mass spectroscopy (TOF-SIMS) and sheet resistance measurements of LTP performances allowed to identify Boron as preferable to BF2 as doping species and to exclude non melting regime from further investigations. Indeed, in Boron implanted samples sheet resistance is found to be lower than in BF2 implanted samples for almost all energy densities, suggesting better activation. In both BF2 and B implants sheet resistance in sub-melted samples is too high to allow measurements. Junction depth seems to be steady in Boron implanted sample whereas it increases at BF2 implanted ones during thermal treatment. So Boron implanted samples show better control of diffusion with no drift of the profile at concentrations below 2 * 10 19 cm −3 . This result is rather surprising, because dopant diffusion takes a large amount of doping at concentration below the solid solubility, so a lower sheet resistance is generally associated with a more diffused profile. In terms of silicon defectivity the Boron implanted sample treated with the highest laser energy is the only one where no dislocations rich layer is observed, on the contrary the silicon close to the surface appears perfectly crystalline.

Ion implantation has been studied relatively little as a nonepitaxial doping method for GaSb due in part to anomalous swelling that occurs at high doses. Aside from beryllium (Be+), there has been little success in identifying other ions as an implant species to dope a GaSb substrate p-type. In this paper, the role of sulfur (S+) as an implant species is investigated for doping GaSb and compared to Be+. Whereas the Be+ implant yields modest hole concentrations as a result of incomplete dopant activation, the S+ implant at a similar dose level realizes p-type carrier concentrations above 1 × 1019 cm−3 with sheet densities as high as 3.5 times the total implanted dose. X-ray diffraction spectroscopy shows that a postimplant anneal at 600 °C successfully recovers the crystallinity of the material, but atomic force microscopy suggests that surface damage may be the cause of the high carrier concentration from the sulfur implant. Preliminary photovoltaic data are reported for a device that employs the sulfur implant technique into a p-type GaSb substrate.Ion implantation has been studied relatively little as a nonepitaxial doping method for GaSb due in part to anomalous swelling that occurs at high doses. Aside from beryllium (Be+), there has been little success in identifying other ions as an implant species to dope a GaSb substrate p-type. In this paper, the role of sulfur (S+) as an implant species is investigated for doping GaSb and compared to Be+. Whereas the Be+ implant yields modest hole concentrations as a result of incomplete dopant activation, the S+ implant at a similar dose level realizes p-type carrier concentrations above 1 × 1019 cm−3 with sheet densities as high as 3.5 times the total implanted dose. X-ray diffraction spectroscopy shows that a postimplant anneal at 600 °C successfully recovers the crystallinity of the material, but atomic force microscopy suggests that surface damage may be the cause of the high carrier concentration from the sulfur implant. Preliminary photovoltaic data are reported for a device that employs the sulfur i...

The neutral beam assisted chemical vapor deposition (NBaCVD) system can control the crystalline phase and the doping efficiency simultaneously by the energy of impinge neutral particle beam. During the deposition process, energetic hydrogen (H) neutral atoms transport their energy to the surface of depositing film to enhance crystallization (crystal volume fraction (Xc) up to 85%) and dopant activation (~1X1020 #/cm3, ~30 cm2/Vs) with low H ratio at near room temperature on the substrate. The increase of H neutral beam flux induces transition of crystal orientation from [111] to [311] at constant Xc and changes the carrier transport path from “grain boundary path” to “grain-to-grain percolation path” and enhances bulk mobility of the Si thin film. The various analysis data of the thin films (XRD, Raman, temperature dependent conductivity, Hall measurement) represent the evidence of very high doping efficiency at near room temperature, obvious nano-crystalline embedded polymorphous phase, and mixed transport (band and percolation) characteristics.

In this study, Fermi level control of point defects during metalorganic chemical vapor deposition (MOCVD) of Mg-doped GaN has been demonstrated by above-bandgap illumination. Resistivity and photoluminescence (PL) measurements are used to investigate the Mg dopant activation of samples with Mg concentration of 2 × 1019 cm−3 grown with and without exposure to ultraviolet (UV) illumination. Samples grown under UV illumination have five orders of magnitude lower resistivity values compared with typical unannealed GaN:Mg samples. The PL spectra of samples grown with UV exposure are similar to the spectra of those grown without UV exposure that were subsequently annealed, indicating a different incorporation of compensating defects during growth. Based on PL and resistivity measurements we show that Fermi level control of point defects during growth of III-nitrides is feasible.

International audience; In this paper, we study the effect of excimer laser annealing on silicon and specifically the oxygen impurities induced versus laser energy density. We show that oxygen penetration from the native oxide occurs during laser annealing, which increases with increasing laser energy. At higher laser energies, oxygen precipitation occurs well below the surface, which is confirmed both by SIMS and optical spectroscopy analyses. The precipitates do not affect the dopant activation in the epitaxial layer.

In this study, low-energy microwave annealing(MWA) is used to activate the germanium material which is new promising and might replace silicon in the future. A novel MWA method with two steps applies to germanium for solid phase epitaxial recrystallization(SPER) and dopants activation. The purpose of the first step MWA at 2P(1.2kW) for 75 sec is to quickly repair the destroyed crystal lattices which are caused by ion implantation to achieve the SPER. The second step MWA at 1.5P(0.9kW) for 300 sec is used to activate the phosphorus dopants effectively without diffusion and de-activation. The target dopant activation level concentration will be more than 1020 cm−3, and sheet resistance decreases to 78 ohm/sq.

Advanced inductively coupled plasma techniques and surface treatments have been used to demonstrate 5nm conformal shallow junctions at low energy with no silicon structure damage. N-type PH3 plasma assisted doping was characterized by dopant diffusion and electrical activation with increasing wafer temperature. Plasma assisted doping at high wafer temperature showed no structure damage even at a high incident energy condition with a bias power applied to the wafer, while a shallow junction of less than 7nm of Xj formation was achieved with low incident energy condition without bias power. Adding a silicon surface modification step when using the decoupled plasma condition prior to PH3 doping was found to enhance the dopant level and lower Rs dramatically. Various annealing techniques were compared to understand the impact to dopant activation and levels to form shallow junctions of less than 7nm.

This work focuses on the development of a novel test structure to evaluate the dynamic behavior of electrical characteristics in the boron-implanted germanium samples during the solid phase epitaxial regrowth (SPER) at low temperature annealing of 360 and 400 °C with various annealing times ranging from 30 to 300 min. In the early stage of SPER annealing, the sheet carrier concentration is increased with annealing time. And then, it will saturate to a level after about 2 hr annealing which implies the completion of SPER process.

CMOS compatible self-aligned access regions for indium gallium arsenide (In 0.53 Ga 0.47 As) implant-free n-type metal oxide semiconductor “eld effect transistors (MOSFETs) are investigated. In situ doped n+source/drain regions are selectively grown by metal-organic vapor phase epitaxy and self-alignedNickel InGaAs alloyed metal contacts are obtained using a self-aligned silicide-like process, where differ-ent process conditions are studied. Soft pre-epitaxy cleaning is followed by X-ray photoelectron spectros-copy, while the Ni InGaAs/III V interface is characterized by back-side SIMS pro“ling. Relevant contactand sheet resistances are measured and integration issues are highlighted. Gate-“rst implant-free self-aligned n-MOSFETs are produced to quantify the impact of Ni InGaAs contacts on the deviceperformance. 2012 Elsevier Ltd. All rights reserved. 1. IntroductionDue to their higher injection velocity, III V compound semicon-ductors and in particular indium gallium arsenide (InGaAs) arebeing studied as possible candidates to replace Si as the channelmaterial in metal oxide semiconductor “eld-effect-transistors(MOSFETs) for digital logic applications. Several challenges haveto be tackled to bene“t from the III Vs superior transport proper-ties and achieve a high drain current performance. Achieving lowresistance self-aligned source/drain access regions suitable forhigh-performance logic at 10 nm node and beyond is one of themost critical challenges. These contacts have to be highly compat-ible with standard CMOS ”ows, scalable to the small-pitch require-ments and thermally stable to stand the back-end process.Several approaches have been tried such as ion implantationwhich has shown its limits due to the too high thermal budget re-quired to achieve a decent S/D dopant activation[1]. Selective epi-taxy of in situ doped InGaAs S/D regions has been done bymolecular beam epitaxy (MBE)[2] and metal-organic vapor phaseepitaxy (MOVPE) [3], achieving a high carrier density in a self-aligned gate-“rst scheme. These two approaches require a III Vcleaning recipe which includes a wet etch down to an etch-stoplayer before regrowth. Etching the channel material prior to S/Dformation is not an option in the case of fully-depleted types ofarchitectures like extremely-thin compound semiconductor oninsulator (ETCSOI).Low contact resistance and self-aligned molybdenum (Mo)metal contacts have been demonstrated using a height-selectiveetching process[4]. However, this process might be dif“cult tomanufacture over large wafer size on scaled devices. A salicide-like(self-aligned silicide) process on III V has been developed using aNickel InGaAs (Ni InGaAs) alloy integrated in a metallic S/D n-MOSFET[5,6] which suffers from a high off-state drain currentdue to the absence of a channel-to-S/D p n junction.In this work we report on a CMOS compatible process ”ow toachieve self-aligned implant-free access regions for In

Microwave annealing of arsenic-doped silicon was employed to achieve nearly complete dopant activation and repair of damage caused by ion implantation. Analysis of Rutherford backscattering spectra suggested that volumetric heating from microwaves can repair ion-implantation damage. Secondary ion mass spectroscopy depth profiling revealed that even with high damage due to implanted arsenic, microwave annealing achieves repair of lattice damage, and electrical activation of dopants without allowing any significant dopant diffusion into the silicon substrate. Surface temperatures greater than 700 °C were achieved within ~ 100 s with assisted microwave heating, marking this as a quick annealing technique when compared to un-assisted annealing. This temperature was sufficient for solid phase epitaxial growth in Si. The temperature profile recorded by a thermocouple-calibarated IR pyrometer was explained based upon the type of losses the sample undergoes while heating. The mechanism for susceptor-assisted microwave heating was dominated by dipole polarization losses in the initial stages of anneal and by Ohmic conduction losses at higher temperatures. Cross-section transmission electron microscopy, along with ion channeling spectra indicated that the silicon lattice regained nearly all of its crystallinity during the microwave anneal. Hall measurement and sheet resistance characterization were used to assess the extent of dopant activation.

We propose a new strategy for in-situ observation of dopant activation process using scanning tunnelling microscopy (STM) technology. Two factor techniques are established within our original STM system combined with liquid-metal-ion-source ion-gun (LMIS-IG/STM): (1) in-situ real-time observation of Si(001)-2×1 surface modified with dopant ions, and (2) in-situ hydrogen passivation of Si(001)-2×1 surface. Sequential STM images of the surface morphological changes are successfully obtained with keeping the original observation area. The hydrogenated Si(001)-2×1 surface is stable enough even under the degraded vacuum conditions which are unavoidable in ion irradiation processes. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Ca5Al2Sb6 is a relatively inexpensive Zintl compound exhibiting promising thermoelectric efficiency at temperatures suitable for waste heat recovery. Motivated by our previous studies of Ca5Al2Sb6 doped with Na and Zn, this study focuses on doping with Mn2+ at the Al3+ site. While Mn is a successful p-type dopant in Ca5Al2Sb6, we find that incomplete dopant activation yields lower hole concentrations than obtained with either previously investigated dopant. High-temperature Hall effect and Seebeck coefficient measurements show a transition from nondegenerate to degenerate semiconducting behavior in Ca5Al2−x Mn x Sb6 samples (x = 0.05, 0.1, 0.2, 0.3, 0.4) with increasing Mn content. Ultimately, no improvement in zT is achieved via Mn doping, due in part to the limited carrier concentration range achieved.

Ion-implantation characteristics and dopant activation behavior of P in Ge have been investigated. A Monte Carlo simulation indicates a smaller projected range and consequently a smaller critical dose of amorphization for Ge compared to Si. The solid-phase epitaxial (SPE) regrowth characteristics of damaged layers for Ge clearly depend on crystal orientation of the substrate in completely amorphized samples, while no orientation dependent regrowth is observed in the partially amorphized samples. These phenomena were explained on the basis of the damage cluster model. In addition, maximum carrier activation coincides with the complete regrowth at annealing temperatures of 300–400 °C in completely amorphized samples. However, higher temperature annealing (500–550 °C) is necessary for maximum carrier activation in partially amorphized samples, although SPE regrowth completes around 250–300 °C. Analysis of the temperature dependence of carrier activation ratio in partially amorphized samples suggests that carrier-activation should be mediated by vacancy-migration.

In this paper, we studied the influence of nitrogen implantation dose on both physical and electrical properties in 3C-SiC grown on Si (100) substrate. Scanning Transmission Electron Microscopy characterizations prove that high dose is responsible for amorphization of the implanted layer and the high defect density after annealing. A high V-shape defect density is still found in the implanted layer after an annealing at 1350°C. By lowering the dose, the layer is less damaged and no amorphization is observed. For the different doses, low Specific Contact Resistances are measured using Ti/Ni contacts. The Specific Contact Resistance value decreases from 8x10-6Ω.cm2for the high dose to 3.2x10­6Ω.cm2with decreasing the dose. Furthermore, the dopant activation ratio, evaluated by quantitative SSRM measurements, is improved at the same time from 17% (for the high dose) to 60% (for the low dose). This work demonstrates that high activation ratio can be achieved consecutively to a nitrogen implantation at reasonable implantation fluence.

The electrical activation of B + implantation at 2 keV to doses of 5.0 × 10 13 –5.0 × 10 15 cm −2 in crystalline and pre-amorphized Ge following annealing at 400 °C for 1.0 h was studied using micro Hall effect measurements. Preamorphization improved activation for all samples with the samples implanted to a dose of 5.0 × 10 15 cm −2 displaying an estimated maximum active B concentration of 4.0 × 10 20 cm −3 as compared to 2.0 × 10 20 cm −3 for the crystalline sample. However, incomplete activation was observed for all samples across the investigated dose range. For the sample implanted to a dose of 5.0 × 10 13 cm −2 , activation values were 7% and 30%, for c-Ge and PA-Ge, respectively. The results suggest the presence of an anomalous clustering phenomenon of shallow B + implants in Ge.

We have investigated the electrical activation in boron doped poly-Si using Hall measurement, 4-point probe, and secondary ion mass spectroscopy. Through doping was conducted using a mass-separated ion implanter with acceleration energies from 20 to 35 keV at doses ranging from 1 × 10 15 /cm 2 to 4 × 10 15 /cm 2 , followed by isothermal rapid-thermal-annealing at temperatures ranging from 550 to 650 °C. The substrates used were poly-Si, produced by two-shot sequential lateral solidification. Reverse annealing, in which a continuous loss of charge carriers occurs, was observed in boron doped poly-Si. We found that implantation conditions play a critical role on dopant activation as well as annealing conditions. We observed that a certain implantation condition does exist where the sheet resistance is not changed upon activation annealing. Damage recovery encountered in activation annealing seems to be closely related to a reverse-annealing phenomenon. We assume that the defect-concentration profile would be more important to activation behavior of poly-Si than integrated defect-density accumulated in the silicon layer.

Good-quality ultrashallow n + p junctions are formed using 5-keV amorphizing As+ implantations followed by a single-shot excimer laser anneal for dopant activation. By using an implant that is self-aligned to the contact windows etched in an oxide isolation layer, straightforward processing of the diodes is achieved with postimplantation processing temperatures kept below 400°C. A possible source of junction leakage at the perimeter caused by dip-etch enlargement of the contact window, also confirmed by transmission electron microscopy (TEM) analysis, is identified, and diode performance is improved by increasing the junction/contact window overlap. The optimum performance in terms of low leakage, shallow junctions, and low resistivity is achieved for 30° tilted implants and by applying a thin laser-reflective aluminum layer. This work isolates the minimum requirements for achieving low-leakage diode characteristics.

In this work, non-intentionally doped cubic silicon carbide (3C-SiC) epilayers grown on (1 0 0) silicon substrates were implanted using nitrogen (N), phosphorus (P) implantations or their co-implantation (N&P). After annealing from 1150 to 1400 °C, Secondary Ion Mass Spectroscopy (SIMS), Atomic Force Microscopy (AFM), Fourier Transformed InfraRed spectroscopy (FTIR), Scanning Spreading Resistance Microscopy (SSRM) and Scanning Transmission Electron Microscopy (STEM) analysis were performed. Specific contact resistances (ρc) of Ti/Ni ohmic contacts were determined using Circular Transfer Length Method (c-TLM) patterns. Our work shows that co-implantation, experimentally investigated for the first time in 3C-SiC, is not beneficial for the doping efficiency. According to the silicon substrate, the post-implantation annealing is limited to 1400 °C. Consecutively to this limit, the total recovering of the lattice does not seem to be possible, whatever are the implanted species. Moreover, as the crystal damages increase when increasing the atomic mass of the implanted species, a comparative study using SSRM measurements proved that, for the same post-implantation annealing treatment, the resistivity of implanted layers depend on the doping species. As a consequence, the lowest ρc value (2.8 × 10−6 Ω cm2) has been obtained (using Ti/Ni 25/100 nm pattern) for a 1400 °C–30 min annealing consecutively to the nitrogen implantation. This value is among the best values obtained on implanted 3C-SiC layers in the literature. Furthermore, for this annealing temperature, a doping activation close to 100% has been evaluated by quantitative SSRM technique which evidences that an efficient dopant activation could be done. The high activation rate obtained on n-type implanted 3C-SiC and the low specific contact resistance achieved with Ti/Ni are very promising for electronic device fabrication.

Ga-doped ZnO films were deposited by pulsed laser deposition (PLD) at 200 °C and 10 mTorr in either pure argon (Ar films) or in oxygen (O 2 films). The bulk resistivity of the Ar films is −4 Ω cm at 300 K, two orders of magnitude lower than that of the O 2 films. In the Ar films, the donor concentration N D as determined by a detailed Hall-effect analysis is close to 100% of the total Ga concentration [Ga] measured by secondary ion mass spectrometry (SIMS), while in the O 2 films N D is less than 50% of [Ga]. Furthermore, the compensation ratio K = N A / N D is >90% for the O 2 films and 2 films have resistivities of about 5×10 −4 Ω cm, approaching those of the Ar films. These results suggest that oxygen-rich environments produce Ga/O complexes that reduce the dopant activation efficiency and thus decrease N D and increase K . Some of these complexes may also contribute to the increase in deep centers observed in photoluminescence.

In this work we demonstrate the fabrication and characterization of high performance junction diodes using annealing temperatures within the temperature range of 300-350?C. The low temperature dopant activation was assisted by a 50nm platinum layer which transforms into platinum germanide during annealing. The fabricated diodes exhibited high forward currents, in excess of 400A/cm2 at ~|0.7|V for both p+/n and n+/p diodes, with forward to reverse ratio IF/IR greater than 104. Best results for the n+/p junctions were obtained at the lower annealing temperature of 300?C. These characteristics compare favorably with the results of either conventional or with Ni or Co assisted dopant activation annealing. The low-temperature annealing in combination with the high forward currents at low bias makes this method suitable for high performance/low operating power applications, utilizing thus high mobility germanium substrates.

The activation behavior of implanted atoms was investigated in P/B ion-shower-doped poly-Si upon thermal annealing. Phosphorous or boron was implanted by ion shower doping at acceleration voltages from 2 kV to 15 kV by using a source gas mixture of PH3/H2 or B2H6/H2. Isochronal annealing was conducted using a tube furnace at temperatures ranging from 400 ◦C to 600 ◦C for 30 min. With some exceptions the sheet resistance decreased as the acceleration voltage increased upon annealing. Reverse annealing, in which the loss of charge carriers continues, was observed to start at around 400 ◦C in the case of B-doping.

One important parameter for modelling emitter recombination is the surface recombination velocity (SRV), which strongly depends on the surface doping concentration and the applied surface passivation. However, for highly phosphorus-doped surfaces with concentrations in excess of 2×1020 cm-3, where not all of the dopant is electrically activated, data is hardly available in the literature. Moreover, the bulk carrier lifetime in such supersaturated near surface regions is unknown. We use an analytical model to describe silicon-nitride-passivated phosphorus-diffused emitters. The model shows excellent agreement with a recently presented numerical solver, deviating less than 1%. In both cases we apply a Fermi-Dirac statistics correction and account for band gap narrowing to calculate the intrinsic carrier density. Our results from measurements of the emitter dark saturation current density indicate that either the SRV or the local carrier lifetime in the supersaturated region are strongly affected by the doping concentration, even if it exceeds the dopant activation limit by far. Assuming only Auger recombination in the supersaturated region, we derive an upper limit for the SRV that depends on the chemical phosphorus surface concentration.