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Ferroelectric thin films of lead titanate (PbTiO3) and lead zirconate titanate (PZT) were grown in a cold-wall low-pressure chemical vapor deposition reactor on silicon substrates with diameters up to 150mm using liquid metal organic precursors including a novel zirconium precursor. Film thickness ranged from 10nm to 700nm. The films were characterized regarding their electrical, optical, and structural properties depending on film composition and deposition conditions. In this paper, we report our results regarding composition effects, the electrical polarization behavior and optical properties like refractive indices and absorption coefficient, which were investigated by spectroscopic ellipsometry for a wide wavelength range. Furthermore some temperature dependent effects of the platinum electrodes are described.

Thermal wave techniques have gained increasing attention in semiconductor process control because they are nondestructive and noncontacting. Recently, in-line and in situ implementations have been investigated. This paper will demonstrate that thermal wave analysis is capable of measuring two major parameters, metal layer thickness and temperature.

In this work, hafnium silicate layers on Si and Ge wafers for gate dielectric application in metal–oxide–semiconductor devices are investigated. Films are deposited by metal–organic (MO)CVD using the single‐source precursor Hf(acac)2(OSitBuMe2)2. This precursor exhibits good properties in terms of hydrolysis stability, volatility, and deposition. However, precursor decomposition is affected by surface conditions. Films deposited on Si wafers reveal high C contamination (up to 20 at %) and low Si content (up to 20 at %). In contrast, for film deposition on Ge wafers, no C contamination can be detected and Si incorporation is delayed until after about 15 nm HfO2dielectric growth. Post‐deposition rapid thermal annealing in an O2atmosphere causes crystallization of deposited films, Si and Ge redistribution in the dielectric, respectively, and interfacial layer growth. However, oxygen annealing was also found to reduce effective oxide thickness (EOT) significantly compared to as‐deposited films, which is attributed to crystallization effects. However, scaling of EOT is limited by that interfacial layer growth. Leakage currents are mainly caused by trap‐related conduction mechanisms. Energy levels of involved traps decrease with increasing crystallization and/or Hf content, and values of 0.5 eV and 1 eV related to Hf and Si bonds, respectively, are obtained.

Zusammenfassung: Eine effiziente medizinische Dokumentation ist für eine traumatologisch ausgerichtete Klinik unter DRG-Bedingungen obligat. Insbesondere in der Handchirurgie besteht aufgrund der Vielzahl von Klassifikationen im Bereich Diagnostik und Therapie ein hoher Differenzierungsbedarf für die klinische Dokumentation. Die Entwicklung eines Werkzeugs, welches im klinischen Prozess die Definition von medizinischen Geschäftsvorgängen vornimmt und gleichzeitig daraus klinische und administrative Informationen erzeugt, war Gegenstand des vorgestellten Entwicklungsprojekts. Durch die Nutzung einer Standardterminologie, innovativer semantischer Netze und einer völlig neuartigen grafischen Dokumentationsoberfläche konnte erfolgreich ein auf die Handchirurgie abgestimmtes Werkzeug entwickelt werden, welches es einer Klinik erlaubt, mit einer einmaligen Datenerfassung in der nötigen wissenschaftlichen Differenziertheit zu dokumentieren und gleichzeitig die DRG-, QS- und BG-erlösrelevanten Merkmale zu erzeugen. Damit steht ein Werkzeug zur Verfügung, das sowohl für den administrativen Bereich eine einfache Datenerfassung ermöglichen kann als auch zukünftig die Plattform für vielfältige Zwecke der klinischen Abbildung und BG-Dokumentation bietet.

AbstractPolyimide (Upilex), polyethyleneterephtalate, polystyrene and polyethylene were irradiated with 20—200 KeV C+, N+, F+, Ar+and Xe+ions to the fluences up to 1017cm−2and the depth profiles of hydrogen and oxygen atoms in the polymer surface layer were determined using standard Rutherford Back-Scattering (RBS) and Elastic Recoil Detection (ERD) techniques. The H and O depth profiles are structureless with no local extremes and with the concentration monotonically increasing from the sample surface to the bulk value typical for pristine polymer. The H and O contents in the irradiated surface layer remain unchanged up to a critical fluence, which is a decreasing function of the energy density deposited by an ion. Then they decline rather rapidly and converge to 50—70% of their original values of unirradiated polymer. The decline rate is roughly the same for all ion/polymer combinations regardless of the ion mass and energy.

PMOS devices with different amounts of nitrogen incorporated into the gate electrode by implantation were manufactured. Nitrogen implantation into the gate electrode of PMOS devices was applied before BF2implantation and annealing by rapid thermal annealing for doping the gate electrode. The thickness of the gate oxides grown at low pressure in dry oxygen by rapid thermal oxidation were 4.1 down to 2.8 nm. The influence of the nitrogen implant on the penetration of boron ions through the ultra-thin gate oxides into the channel region was investigated by electrical and SIMS measurements. Boron was effectively prevented from diffusion by high nitrogen concentrations at the polysilicon/gate oxide interface without degrading the reliability. In return, increased sheet resistivities and gate depletion have to be taken into account when high nitrogen concentrations are incorporated within the polysilicon gate electrode.

The reliability of oxynitrides with thicknesses from 4.0 nm down to 2.6 nm was investigated. The oxynitrides were grown by rapid thermal processing at reduced pressure in gas atmospheres of N2O, a 50% mixture of N2O and O2, and O2. The concentrations of the nitrogen incorporated into the oxide during growth were found to be dependent on both, oxidation pressure and oxidation atmosphere. Reliability tests were performed by constant voltage stress on MOS capacitors. The measurements revealed that oxynitridation in N2O containing ambient can improve reliability even for oxides thinner than 3 nm. The nitrogen concentration, which is beneficial to oxide reliability, shows strong dependence on oxide thickness.

Abstract: Tissue changes in ischaemic stroke are detectable by diffusion-weighted MRI (DWI) within minutes of the onset of symptoms. However, in daily routine CT is still the preferred imaging modality for patients with acute stroke. Our purpose of this study was to determine how early and reliably ischaemic brain infarcts can be identified by CT and DWI. Three neuroradiologists, blinded to clinical signs but aware that they were dealing with stroke, analysed the CT and DWI of 31 patients with an acute ischaemic stroke. We calculated k-values to analyse inter-rater variability. The ratings were compared with follow-up studies showing the extent of the infarct. The combined assessment of all observers gave positive findings in 77.4 % of all CT examinations, with k = 0.58. Areas of high signal were seen on all DWI studies by all observers (k = 1). Estimation of the extent of the infarct based on DWI yielded k = 0.70 and that based on CT k = 0.39. DWI was much more reliable than CT in the detection of early ischaemic lesions and we believe that it should be used in acute ischaemic stroke before aggressive therapeutic intervention.

Polyethylene (PE) foils were modified by irradiation with ArE+and XeE+ions to different fluences and different physico-chemical properties of the irradiated PE were studied in relation to adhesion and proliferation of keratinocytes on the modified surface. Changes in the PE surface roughness were examined using the AFM technique, the production of conjugated double bonds and oxidized structures by UV-VIS and FTIR techniques respectively. The surface polarity was determined by measuring surface contact angle and two-point technique was used for the determination of PE sheet resistance. Adhesion and proliferation of keratinocytes was characterized using the MTT-test. The ion irradiation leads to creation of conjugated double bonds which, together with progressive carbonization, contribute to the observed decrease of sheet resistance. Oxidation of the irradiated PE surface layer during the ion implantation is observed. Besides oxidation, the PE surface polarity is affected by other factors. The observed increase of the PE surface roughness due to the ion irradiation is inversely proportional to the ion size. The adhesion and proliferation of keratinocytes on the ion irradiated PE is significantly higher than on the pristine PE. Distribution of results in keratinocyte cultivation and the number of cells is related to the ion fluence applied and to ion species as well.

Oxide reliability of oxynitrides with thicknesses between 3.6 and 2.6 nm was investigated. The oxynitrides were grown at reduced pressure in gas atmospheres containing different ratios of N2O and O2concentrations. The concentrations of the nitrogen incorporated into the oxide were found to be dependent on both, oxidation pressure and oxidation ambience. Further, reliability tests revealed that the nitrogen concentration, which is beneficial to oxide reliability, shows a strong dependence on oxide thickness.

PMOS devices with different amounts of nitrogen implanted into the gate electrode before doping with BF2implantation and implant anneal were manufactured. The thicknesses of the gate oxides grown in dry oxygen by RTP were 4.1 down to 2.8 nm. The implant anneal was also performed by RTP. The influence of the nitrogen on the penetration of boron ions through the ultra-thin gate oxides into the channel region was investigated by electrical and SIMS measurements. Boron was effectively prevented from diffusion by high nitrogen concentrations at the polysilicon/gate oxide interface without degrading the reliability. In return, increased sheet resistivities and gate depletion have to be taken into account by high nitrogen concentrations within the polysilicon gate electrode.

A spectroscopic ellipsometer was integrated in a vertical furnace for measurement and control during chemical vapor deposition and thermal oxidation processes. The major goal of this activity was to adapt the ellipsometer arrangement to the furnace geometry with a minimum impact on the furnace process performance. Modifications in the furnace geometry were restricted as far as possible, to show that a fast integration in existing industrial equipment with minor costs can be done. This aim led to a novel beam-guiding system. This setup has been used for the in situ characterization of polysilicon formation, inside the vertical furnace during high temperature processes. The polysilicon-on-oxide structures were modeled using the Bruggeman effective-medium approximation (B-EMA). The crystallization process of amorphous silicon layers during annealing at 600°C has been monitored. Layer thickness and the degree of crystallinity can be obtained simultaneously. The crystallinity can be described in the optical model using a ‘mixture’ of amorphous silicon and single-crystalline silicon in the B-EMA.

Impurity incorporation due to localized beam processing by focused ion beams (FIBs) and electron beams (EBs) such as physical sputtering, gas-assisted etching (GAE) using iodine gas and beam-assisted deposition using (CH3)3CH3C5H9Pt precursor gas has been investigated by a medium energy nuclear microprobe. RBS mapping on incorporated impurities has been performed using 300 keV Be2+beams with a beam spot size of 80 nm. RBS mapping images for physically sputtered and GAE areas indicate the localized Ga and I atoms distributions from the Ga FIB and from the etchant gas, respectively. The amount of Ga in the GAE area was estimated to be ∼2.7 times smaller than that in the physically sputtered area. RBS mapping images for FIB assisted Pt deposited areas revealed that Pt and Ga atoms were distributed in the processed areas, while C atoms resided beyond the processed areas.

The localized Cu deposition on Si by 30 keV Ga+focused ion beam (FIB) using precursor gas has been investigated by a 300 keV Be2+nuclear microprobe with a beam spot diameter of 80 nm. The Cu deposition and impurity incorporation were compared at different temperatures of precursor gas. The distribution of deposited Cu, Ga from the ion beam itself and low-Z elements from the precursor gas was obtained at and nearby the deposited areas by RBS mapping images. An RBS mapping image of Cu atoms for FIB induced deposition indicated the uniform Cu films in the case of lower temperature (25°C and 37°C) of precursor. On the contrary in the case of higher temperature (43°C and 50°C) of precursor gas, the RBS mapping image of Cu atoms shows irregular distribution and incorporated impurities. The micro-RBS spectra indicated the deposition behavior that the thickness of Cu layers increased with the decrease in temperature of precursor gas due to the enhancement in the adsorption of precursor gas on the target surface.

Models for the description of implantation profiles in multilayer targets are compared. It is found that all analytical models have severe limitations if the different layers possess very different stopping powers. The best description of multilayer targets is obtained by a combination model using density scaling of the range and integration to account for mass conservation.

Abstract: The important role of damage dependent electrical activation in the case of boron implanted silicon layers is whown by comparing measured acceptor concentration profiles in differently amorphized silicon layers. It is shown that the amorphous layer is completely recrystallized after a 650 C anneal for 10 min and the implanted boron is electrically active. In the heavily damaged but not amorphous region underneath the amorphous layer the implanted boron is hardly electrically active after this temperature treatment. At higher annealing temperatures the electrical activity increases, but 900 C are required for complete activation of the implanted boron. These results indicate that the process to activate the implanted boron electrically is strongly damage dependent. We thus found a new contribution to the understanding of the annealing behavior of implanted layers.

Abstract: The annealing behavior of arsenic-implanted silicon under scanned cw CO2-laser irradiation from front and back surfaces is investigated. Ellipsometry, Hall effect, Rutherford backscattering measurements and neutron activation analysis indicate an enhancement of annealing efficiency by laser irradiation from the back surface, which provides complete recovery of crystal damage, high substitutionality and electrical activation of implanted arsenic atoms without redistribution of concentration profile. The enhancement of annealing efficiency under back-surface irradiation is explained by the difference in laser reflection from the front and back surface of silicon wafers. No differences in the results are found for scanned and static annealing.

Abstract: The implantation of nitrogen into silicon to produce Si3N4 layers was investigated to find an alternative to CVD-Si3N4 layers used in ISOPLANAR-and LOCOS-technology. The technological properties of the implanted Si3N4 layers in respect to oxidation inhibition and etching are comparable or superior to CVD-Si3N4 layers. The implanted layers are more resistent against oxidation for nitrogen doses of 2.41017 cm−2 at 30keV. The etching behavior is comparable for both types of Si3N4-layers. In the implanted layers no pinholes are found and threre is no formation of a bird's beak, as is well known in the case of CVD-nitride.

Abstract: The diffusion behaviour of implanted boron in silicon was investigated using the10B(n,α)7 Li nuclear reaction. An anomalous behavior with a strong reduction of the diffusivity above an effective solubility limit at 1.51019, 61019, and 1.11020 cm−3 was found for annealing temperatures of 800, 900, and 1,000C, respectively.

Abstract: Nitrogen ions were implanted in GaAs1−xPx (x=0.4; 0.65) at room temperature at various doses from 51012 cm−2 to 51015 cm−2 and annealed at temperatures from 600C up to 950C using a sputtered SiO2 encapsulation to investigate the possibility of creating isoelectronic traps by ion implantation. Photoluminescence and channeling measurements were performed to characterize implanted layers. The effects of damage induced by optically inactive neon ion implantation on photoluminescence spectrum were also investigated. By channeling measurements it was found that damage induced by nitrogen implantation is removed by annealing at 800C. A nitrogen induced emission intensity comparable to the intensity of band gap emission for unimplanted material was observed for implanted GaAs0.6P0.4 after annealing at 850C, while an enhancement of the emission intensity by a factor of 180 as compared with an unimplanted material was observed for implanted GaAs0.35P0.65 after annealing at 950C. An anomalous diffusion of nitrogen atoms was found for implanted GaAs0.6P0.4 after annealing at and above 900C.

Abstract: The activation energy for the annealing of arsenic implanted layers in silicon was studied by isothermal and isochronal annealing experiments. Different mechanisms are responsible for the annealing behavior. At low doses and at temperatures below 700�C a doubly charged complex is formed with an activation energy of 0.86 eV which dissociates at higher temperatures with an activation energy of 3.58 eV. At high doses which result in the formation of an amorphous layer a single activation energy of 2.75 eV is measured.

Abstract: The range parameters of boron in silicon have been measured using the10B(n,α)7 Li-nuclear reaction. The results indicate that the distributions can be perfectly modeled using Pearson IV distributions with 4 moments. The range is very well described by theoretical calculations, whereas the higher moments show a strong deviation from theory.

From a compilation of known literature, the substitutional fraction of boron in silicon is depicted in a diagram as a function of implantation dose and annealing temperature. Samples implanted at 1 1016 B/cm2 and annealed at 900, 1000 and 1100°C for 1 hour each are examined by the (n, α) method and compared to the RBS signal of the host atoms in various directions. Our results indicate a gradual transition from completely random positions after 900°C anneal to substitutional sites after 1100°C anneal.The observation of random positions for B in Si, annealed at 900°C, disagrees with earlier experiments after application of (p, α) reactions. We ascribe the differences to proton irradiation induced boron diffusion in those former accelerator experiments by other authors.Our results for the samples annealed above 900°C indicate lattice positions for the interstitial boron fraction which were not yet discussed in the literature.After 1100°C anneal, nearly all B atoms are found on positions slightly (approx. 7%) displaced from substitutional sites. This may result from the formation of small B2 or B3 clusters during the cooling period of the thermal annealing procedure.