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CF4 plasma treatment on n+-Si wafers as bottom electrodes (BEs) of poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)) metal-ferroelectric-metal (MFM) capacitors has been investigated in this study. Prior to the fabrication of MFM capacitors, comprehensive material analyses are administered to identify the incorporation of fluorine atoms into P(VDF-TrFE) copolymers, revealing an enrichment in C2HF3 (trifluoroethylene) bonds and an improvement in the crystallinity of the film. The P(VDF-TrFE) MFM capacitors with CF4-plasma-treated n+-Si wafers show a shallower charge trapping level of 0.154–0.226 eV extracted from the Frenkel–Poole (F–P) emission at 213–273 K for the BE injection compared to that for the top electrode (TE) injection, which is ascribed to the passivation of deep traps by the fluorine atoms that diffused from the n+-Si wafers. Thus, asymmetric remanent polarization and a negative internal bias field are obtained because of the significant increase in the β-phase at the bottom of the P(VDF-TrFE) films. With the CF4 plasma treatment for 1 min, the P(VDF-TrFE) MFM capacitors demonstrate a remanent polarization (2Pr) of 6.58 µC/cm2, a coercive electric field (Ec) of 0.47 MV/cm and stability for more than 3 × 104 cycles with negligible fatigue, making the fluorine-incorporated P(VDF-TrFE) copolymers suitable for future high-performance nonvolatile memory applications.

This study investigated the effects of the bottom electrode (BE) on the resistive switching (RS) of silver programmable metallization cells (Ag-PMCs) with gadolinium oxide and aluminum oxide (Gd x O y /Al x O y ) solid electrolytes (SEs). The RS mechanisms of memories with different bottom electrodes were proposed based on the temperature dependence of the resistance at low resistance state (LRS) and current–voltage ( I–V ) fitting at high resistance state (HRS). The Schottky emission was dominant in the resistive switching of the memory with an iridium bottom electrode (Ir-BE), whereas in the memories with n + -Si and nickel (Ni) bottom electrodes, silver and both silver and nickel ions dominated the resistive switching, respectively. Additionally, the Ag-PMC with Ni-BE had a high resistance ratio of more than 10 7 as a result of the extremely low resistance of roughly 50 Ω at LRS. The Ag-PMCs with Gd x O y /Al x O y SEs and Ni-BE exhibited a retention behavior of more than 10 4 s and an endurance of more than 500 cycles with a resistance ratio of at least four orders of magnitude, which is promising for future high-density nonvolatile memory applications.

A conductive polymeric film, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), is surface-modified by nitrogen plasma in order to enhance its piezoresistive characteristics. With an optimized 3 min nitrogen plasma surface modification, the piezoresistive sensitivity and response were significantly enhanced. Hall measurements and temperature-dependent conductance measurements are carried out to determine the electron-hopping behavior of nitrogen-plasma-modified PEDOT:PSS films, suppressing the horizontal carrier conducting pathway in the PEDOT:PSS piezoresistive pressure sensors. X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy are applied to observe the PEDOT:PSS film surface after being modified with nitrogen plasma. The presence of sulfamate (SO3–NH2) and thiocyanate (S–C≡N) groups indicates a breaking of the electrostatic bonding between PEDOT and PSS and a modification of the conductive PEDOT conjugated chain. At the film surface, the formation of thiocyanate groups of ...

Characteristics of chemically-synthesized (CS) gold nanoparticle (Au-NP) nonvolatile memories (NVMs) with low-damage NH 3 plasma treatment on a tunneling oxide (TO) layer have been investigated. Although the dot density of CS Au-NPs is decreased, the programming efficiency of memories with optimized NH 3 plasma treatment condition is enhanced due to the formation of a trapezoid-like energy band diagram of the TO layer by nitrogen incorporation. With the extraction of relative permittivity and electron affinity of the TO layer, the capacitance-voltage ( C - V ) and programming behaviors of CS Au-NP memories with low-damage NH 3 plasma treatment on the TO layer are well-fitted by the TCAD (Technology Computer-Aided-Design) simulation. Further, the built-in electric field induced by the trapezoid-like energy band diagram of the TO layer can suppress the leakage current of the TO layer, thereby improving the data retention properties. The low-damage NH 3 plasma treatment that results in no plasma damage to the TO layer has been proposed to be the probable candidate for future NVM applications.

Sputtered titanium nitride (TiN) with a novel N2 ratio adjustment and rapid thermal annealing (RTA) treatment are proposed in order to optimize pH sensing performance of electrolyte-insulator-semiconductor (EIS) structure. Selection of this methodology, which can be easily applied into standard CMOS and DRAM technology, results from the fact that TiN is a well-verified material as a buffer or a barrier layer. It was concluded that pH sensitivity of the order of 60.5 mV/pH and linearity of 99.9% could be obtained for a TiN/SiO2 EIS structure treated with N2 ratio of 20% and RTA at 800 °C, which could be a good candidate in sensor applications. This performance is stable for more than two months. Higher surface roughness shown in atomic force microscope (AFM) analysis and high oxygen level in sputtering process shown in x-ray photo photoelectron spectroscopy (XPS) could be the reasons for the high sensitivity of the fabricated TiN sensing layer.

Carrier injection and charge loss characteristics of nonvolatile memories with chemically-synthesized (CS) and vacuum-deposited (VD) gold nanoparticles (Au-NPs) have been investigated. Compared to CS counterparts, the memories with VD Au-NPs exhibit a higher dot density of 3.77 × 1011 cm−2, leading to a larger memory window. Further, the energy from valence-band edge to vacuum level (EVB_vac) of tunneling oxide for the samples with CS and VD Au-NPs is found to be 9.04 and 9.85 eV respectively. The small EVB_vac value of the memories with CS Au-NPs is resulted from the formation of a thin chemical oxide (SiOx) on thermally-grown SiO2 tunneling layer during the chemically synthesized process, contributing to a slow erasing behavior. Besides, the programming of the memories with VD Au-NPs is saturated at high gate bias, which has been well-explained by the electrons induced potential coupling between Au-NPs. Superior data retention property and high temperature dependence of charge loss are observed for the memories with CS Au-NPs, which can be ascribed to the thick tunneling oxide layer by the additional SiOx film.

Gold-nanoparticle (Au-NP) non-volatile memories (NVMs) with low-damage CF4 plasma treatment on the blocking oxide (BO) layer have been investigated to present the gate injection of the holes. These holes, injected from the Al gate with the positive gate bias, were explained by the bandgap engineering of the gradually-fluorinated BO layer and the effective work function modulation of the Al gate. The Si–F complex in the BO layer was analyzed by X-ray photoelectron spectroscopy (XPS), while the depth of fluorine incorporation was verified using a secondary ion mass spectrometer (SIMS). In addition, the valence band modification of the fluorinated BO layer was examined by ultraviolet photoelectron spectroscopy (UPS) to support the bandgap engineering. The reactive power of the CF4 plasma treatment on the BO layer was modified to increase the electric field of the BO layer and raise the effective work function of the Al gate, leading to the hole-injection from the gate. The injected holes are trapped at the interface between the gold-nanoparticles (Au-NPs) and the tunneling oxide (TO) layer, resulting in superior data retention properties such as an extremely low charge loss of 5.7% at 104 s and a nearly negligible increase in charge loss at 85 °C of the CF4-plasma-treated Au-NP NVMs, which can be applied in highly reliable consumer electronics.

The characteristics of hybrid gadolinium oxide nanocrystal (Gd 2 O 3 -NC) and gadolinium oxide charge trapping (Gd 2 O 3 -CT) memories were investigated with different Gd 2 O 3 film thickness. By performing the rapid thermal annealing on Gd 2 O 3 films with different thickness, the Gd 2 O 3 -NCs with the diameter of 6–9 nm for charge storage, surrounded by the amorphous Gd 2 O 3 ( α -Gd 2 O 3 ) layer, were formed. The α -Gd 2 O 3 layer was considered to be the charge trapping layer, resulting in the large memory window of Gd 2 O 3 -NC/CT memories with thick Gd 2 O 3 film. The charge trapping energy level of the Gd 2 O 3 -NCs and α -Gd 2 O 3 layer was extracted to be 0.16 and 0.45 eV respectively by using the temperature-dependent retention measurement. Further, after a 10 6 program/erase cycling operation, the memory with thin Gd 2 O 3 film can be predicted to sustain a 94% memory window of the first cycling one while the memory with thick Gd 2 O 3 film suffered from a 30% charge loss because of the traps within the α -Gd 2 O 3 layer. The Gd 2 O 3 film thickness of 10 nm was optimized to exhibit superior performances of the Gd 2 O 3 -NC/CT memory, which can be applied into the nonvolatile memory.

The effect of the CF 4 plasma treatment on the gadolinium oxide (Gd x O y ) thin films for the resistive random access memory (RRAM) applications was investigated. The material properties of the fluorine incorporated Gd x O y films were analyzed by the X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS) and ultraviolet–visible spectroscopy (UV–VIS). Further, the set and reset voltages of the Pt/Gd x O y /W RRAM devices with the CF 4 plasma treatment were effectively reduced to −1.15 and 2.1 V respectively owing to the low Schottky barrier height. The formation of Gd F bonds can prevent the oxygen atoms from out-diffusing through Pt grain boundaries into the atmosphere, leading to the superior retention characteristics for over 10 4 s. The CF 4 plasma treated Gd x O y RRAMs can sustain a resistance ratio of 10 2 for more than 800 times stable set/reset cycling, suitable for future low-voltage and high-performance nonvolatile memory operation.

In this article, the detection of ammonium (NH4+) ion using nanoscaled 2-nm thick atomic layer deposition (ALD)-hafnium oxide (HfO2) films with post rapid thermal annealing (RTA) and carbon tetrafluoride (CF4) plasma treatments based on light-addressable potentiometric sensor (LAPS) was investigated. 2-nm thick ALD-HfO2 films with post RTA and CF4 plasma treatment were fabricated as sensitive membranes, respectively. Measured pNH4 response from 2-nm thick ALD-HfO2 LAPS was decreased with increasing annealing temperature and was improved under CF4 plasma treatment. The optimum pNH4-sensitivity of 37 mV/pNH4 was achieved with both 900 °C annealing and 5 min CF4 plasma on ALD-HfO2 LAPS. When compared to the same structure without plasma treatment, the sensitivity was improved by approximate fourfold. Based on X-ray photoelectron spectroscopy (XPS) analysis, increased pNH4-sensitivity was attributed to polar dipole (F O) formation in ALD-HfO2 thin films due to the incorporation of fluorine by CF4 plasma treatment. To assess interferences from other ions (H+, Na+, K+, and Ca2+), selectivity coefficients obtained by fixed interference method (FIM) measurements were presented.

In this study, we investigate the oxygen plasma-immersion-ion-implantation (PIII) treatment on the characteristics of tungsten nanocrystal (W-NC) nonvolatile memories. The oxygen PIII has multi-species plasma of O+, O++ and O2+, and the simulation can successfully fit the oxygen secondary ion mass spectrometry (SIMS) profile. It is observed that the oxygen PIII treatment can effectively improve the disturbance effect and endurance characteristics for over 1.5 V memory window under 104 program/erase cycling. The discrete W-NCs are clearly observed from the high-resolution transmission electron microscopy (HRTEM) image and confirmed by the energy-dispersive X-ray (EDX) analysis. Nevertheless, some damage of O2 PIII on tunneling oxide and silicon surface may lead to the inadequate retention characteristics. By fine-tuning the plasma ions, the PIII technique can be applied into future nonvolatile memory manufacturing.

Trapping characteristics of forming gas-annealed Gd2O3 nanocrystal (Gd2O3-NC) memories were studied in detail. The trapping energy can be obtained from the data retention characteristic for different absolute temperature (T). The discharging time (τ) was extracted from a linear fitting curve of the data retention characteristic. From the relationship between ln(1/τT2) and 1/kT, the trapping energy was evaluated. Based on the retention properties, the discharge mechanisms of electrons in shallow and deep traps are correlated to the charge loss time. The observed values of the trapping energy demonstrated that deep traps are passivated by hydrogen species after FGA treatment; the difference of programming and erasing (P/E) speed of the memories between the samples with- and without-FGA treatment can be explained by this passivation process. A band diagram is proposed to explain the behavior of the charge loss mechanism. The fact that the endurance of Gd2O3-NC memories are not significantly degraded by the FGA treatment indicates that, though the deep traps are passivated by hydrogen, the reliability of the Gd2O3-NC memories is not affected. The method of FGA treatment enables the determination of the discharge process in nanocrystal memories.

The microstructure evolution of sputtered gadolinium oxide nanocrystal (NC) memory devices upon annealing has been characterized in detail by transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). TEM results indicate that the as-deposited film is composed of metallic Gd clusters embedded in an amorphous Gd x O y matrix. The Gd clusters undergo phase transformation to oxide NCs upon annealing, reaching a maximum density of 7.9–9.1 × 10 11 cm − 2 at 850 °C, which is consistent with the largest memory window width. Upon annealing at even higher temperature, TEM diffraction patterns and XPS composition profiles indicate apparent Si diffusion into the NC layer, probably from the SiO 2 tunneling oxide or the Si substrate, leading to the formation of gadolinium silicate NCs. The presence of silicate NCs gradually deteriorates the device performance due to the reduction of barrier confinement for stored charges, although the dot density is only marginally decreased. The results suggest that the optimum memory device performance is dominated by not only the most considered size and density of NCs, but also the composition and phase inside.

In this study, the memory characteristic of a gadolinium (Gd)-based oxide charge storage layer was demonstrated. The metal/oxide/high-k/oxide/silicon (MOHOS)-type memories were fabricated by using two different charge storage layers. The Gd2O3 nanocrystal (Gd2O3-NC) was used as a charge storage layer due to the discrete nodes, while the HfGdO high-k material was used as a charge storage layer due to the existence of discrete traps. In the case of Gd2O3-NC memory, a combination of X-ray photoelectron spectroscopy (XPS) and ultraviolet (UV)–visible spectrophotometer analysis was used in this study to extract the valence band location and the band-gap of the Gd2O3-NC layer. The retention characteristic was also analyzed to extract the trapping level in Gd2O3-NC, based on the relationship between trapping energy and discharging time. A band diagram was created to characterize the memory effect of the Gd2O3-NC memory. In the case of HfGdO SONOS-type memory, the electrical and physical studies were conducted for HfGdO charge-trapping layers deposited by a dual-sputtered method for silicon–oxide–nitride–oxide–silicon (SONOS)-type nonvolatile memory. The Hf/Gd dual-sputtered power ratio and the Ar/O2 gas flow ratio were optimized. It was observed that the nonstoichiometric GdO (2 0 0) structure may be the main charge-trapping site for the memory. The memory samples with Hf/Gd = 150/150 and Ar/O2 = 20/5 exhibited better electrical performance. A physical model is proposed to further explain the retention mechanism.

Multilevel resistive switching (RS) of gadolinium oxide (GdxOy) memristors treated by hydrogen plasma immersion ion implantation (PIII) was investigated. Hydrogen ions were implanted at the Pt/GdxOy interface to modify the oxygen-vacancy distribution, which was examined by the X-ray photoelectron spectroscopy. After the hydrogen PIII treatment, a forming process is needed to operate the GdxOy memristors and the RS mechanism is changed from Schottky emission to space-charge-limited conduction. Superior multilevel RS properties such as data retention for more than 104 s at 85°C, and sequentially cycling test for more than 103 times with a resistance ratio of approximately one order of magnitude between each state are realized, making the future high-density flash memory possible.

The mechanism of different pH sensitivities on single and stacked layer silicon nitride (Si3N4)-electrolyte insulator semiconductor (EIS) structures was investigated for the application of an inorganic ion sensitive field effect transistor (ISFET) and reference field effect transistor (REFET) pair. The capacitance–voltage (C–V) hysteresis effect of the EIS structures was measured. In addition, pH sensitivity was evaluated with different sweep directions and ranges of the substrate bias. Based on the hysteresis results, a pH-dependent trapping effect was found to decrease the pH sensitivity on a single Si3N4 sensing membrane EIS structure.

A novel HfO 2 thin film with SF 6 plasma treatment as ion selective membrane on electrolyte–insulator–semiconductor structure for pH-sensor was proposed. The sensing characteristics on hydrogen ion detection and the non-ideal effects including drift effect, hysteresis phenomenon, and responses on interference ions were all presented in this article. The results show that the slight increase of pH-sensitivity is achieved and the non-ideal effects are improved after SF 6 plasma treatment. It is finally concluded that the HfO 2 thin film with SF 6 plasma treatment as ion selective membrane is suitable for pH detection and the optimum condition is 5 min for SF 6 plasma treatment.

In this work, we describe the characteristics of silicon surface fluorine implantation (SSFI) for HfO2 films with high-temperature postdeposition annealing. The thermal stability of HfO2 gate dielectrics is much improved owing to the incorporation of fluorine into HfO2 thin films. The gate leakage current of the SSFI HfO2 films is about three orders less than that of samples without any fluorine implantation. In addition, improvements in stress-induced leakage current (SILC) and charge trapping characteristics are realized in the HfO2 films with the SSFI. The incorporation of fluorine atoms into the HfO2 films reduces not only interface dangling bonds but also bulk traps, which is responsible for the improvements in properties.

NH3 plasma treatment on interfacial SiO2 to reduce the interface dipole effect.Energy band diagram of HfO2 films established by XPS and UV-VIS.Band-gap increase due to tetragonal phase of nitrogen doped HfO2 examined by XRD.Negligible oxygen ions movement between HfO2/nitrided SiO2 for zero dipole interface. The NH3 plasma treatment on interfacial SiO2 has been proposed to reduce the interface dipole effect of HfO2/SiO2 gate dielectric stacks. The X-ray photoelectron spectroscopy (XPS) and ultraviolet-visible spectroscopy (UV-VIS) were used to establish the band diagram of the HfO2 films. The tetragonal crystallization phase of the HfO2 films examined by X-ray diffraction (XRD) was responsible for the band-gap increase during the NH3 plasma treatment. By using the Schottky emission and Fowler-Nordheim (F-N) tunneling, the effective electron barrier height of the Al/HfO2 gate stacks can be determined. Thus, the interface dipole and Fermi-level pinning induced flat-band voltage shifts of the Al/HfO2/SiO2/p-Si structure subjected to different NH3 plasma treatment conditions were obtained. It was found that the NH3 plasma treatment for about 4min was sufficient for achieving the zero dipole interface of the HfO2/SiO2 gate dielectric stack due to the negligible movement of the oxygen ions between the HfO2 and the nitrided oxide.

In this paper, we demonstrate gadolinium oxide RRAM with nitrogen plasma immersion ion implantation (PIII) treatment technique at first time. For nitrogen plasma treatment, the nitrogen ions were incorporated with gadolinium oxide. We controlled the implantation voltage that the nitrogen ions exist near the surface of gadolinium oxide and it was forming a GdxOyNz layer. This can reduce the leakage current to reach a low current and power consumption operation. In addition, the retention and endurance characteristics were also improved.

In-Ga-Zn-O (IGZO) was widely applied in the substrate of TFT to replace a-Si in recent year. In this study, IGZO layer with thickness of 70 nm is first proposed as a pH sensing membrane directly on P-type Si substrate acting as an extended gate of conventional extended-gate field-effect Transistor (EGFET). Material criteria of extended gate electrode are low resistance and high capacitance. Therefore, Ar/O2 ratio was modified in the rf sputtering with IGZO target. Post deposition anneal was also performed to check the sheet resistance and pH sensing performance. EGFETs were measured in standard pH buffer solution by using B1500A and constant voltage constant current (CVCC) circuit. Similar IDS-VGS curves including transconductance (Gm) and substrate swing (S.S.) are obtained in various sputtering conditions of IGZO compared to commercial NMOSFET in CD4007. pH application range is only between pH 2 to pH 10. IGZO-EGFET prepared by Ar/O2 ambience of 24/1 in sputtering can have a sensitivity of 59.5 mV/pH. Lower sensitivity and linearity can be observed in the samples with RTA treament at higher temp and in O2 ambience. N2 anneal at 500°C can be used to improve pH sensing performance for IGZO-EGFET prepared by Ar/O2 ambience of 20/5 in sputtering. Nano-IGZO layer is verified to be the sensing membrane in EGFET to have a high sensitivity of 59.5 mV/pH for the first time. More studies on enlargement pH application range and minimization of non-ideal effect still need to be investigated.

As a potential candidate for future nonvolatile memory (NVM) application, the discrete charge storage nodes formed as the nanocrystal (NC) structure has been caught much attention. Among the NC materials, high-k metal oxide is the unique one due to the mixed chemical reactions during high temperature forming process. The over-view of gadolinium oxide nanocrystal (Gd 2 O 3 -NC) memory is revealed in this paper. Gd 2 O 3 -NC was formed by one step rapid thermal annealing treated on the amorphous Gd 2 O 3 film prepared by sputter system. The optical tests were conducted to exam the bandgap value of the Gd 2 O 3 -NC and the x-ray tests were conducted to exam the valence band offset. The charge trapping phenomenon can be characterized by the retention tests for various temperatures. Forming gas annealing was treated on the Gd 2 O 3 -NC to passivate the deep traps. A band engineered method by CF 4 plasma treatment was also conducted to improve the memory characteristics.

In this article, the development of a potassium ion sensor based on the fluorinated-HfO 2 using fluorine (F19+) ion implantation on Electrolyte-Insulator-Semiconductor (EIS) structure is proposed. To concentrate the F atom within a shallow region on HfO 2 sensing membrane surface, relatively low implant power and big tilt angle are chosen. With suitable F19+ implant dosage, the pK sensitivity can be effectively improved from 18.19 to 112 mV/pK, and relatively low drift coefficient of 2.62 mV/h is also achieved in 10 mM potassium electrolyte. To investigate the surface roughness and the fluorine depth profile of the implanted-HfO 2 films, physics analysis including AFM and XPS are both performed.

In this work, discussing the detection of NH 4 + ion based on LAPS with functionalized 2 nm-thick ALD-HfO 2 film using RTA and CF 4 plasma is demonstrated. The annealing treatment at 500, 700, and 900°C were performed on ALD-HfO 2 film and the plasma treatment for 1, 3, and 5 min were performed on ALD-HfO 2 film with 900°C annealing. In the results, the response for NH 4 + ion detection was decreased with increasing annealing temperature and increased with increasing plasma time. The optimum sensitivity of 37.28mV/pNH 4 was achieved with 900°C annealing and 5 min CF 4 plasma.

In this article, we demonstrate a samarium oxide (Sm2O3) electrolyte–insulator–semiconductor (EIS) sensor with nitrogen plasma immersion ion implantation (PIII) treatment for anion sensing and interfering characterization. Chloride (Cl−), nitrite (NO2−), and nitrate (NO3−) ions were detected, and the sensitivity was about 49.75 mV/pCl, 53.8 mV/pNO2, and 56.19 mV/pNO3, respectively. Ion sensitivity was enhanced with the increase in ionic radius of the target ion. Titration was performed to analyze the interference of anions. To assess interferences from these ions (Cl−, NO2−, and NO3−), selectivity coefficients obtained by fixed interference method (FIM) measurements were presented. In result, the coefficients indicate that the interference can be ignored. Furthermore, characteristics of drift demonstrates that the sample exhibits long-term stability for significantly lower drift of chloride, nitrite, and nitrate ions, respectively. The Sm2O3 EIS sensor with nitrogen PIII treatment exhibits superior anion sensitivity, selectivity, and stability; therefore, this sensor is suitable for future biosensing applications.

Characteristics improvement of gadolinium oxide (GdxOy) resistive random access memories (RRAMs) treated by hydrogen plasma immersion ion implantation (PIII) was investigated. With the hydrogen PIII treatment, the GdxOy RRAMs exhibited low set/reset voltages and a high resistance ratio, which were attributed to the enhanced movement of oxygen ions within the GdxOy films and the increased Schottky barrier height at Pt/GdxOy interface, respectively. The resistive switching mechanism of GdxOy RRAMs was dominated by Schottky emission, as proved by the area dependence of the resistance in the low resistance state. After the hydrogen PIII treatment, a retention time of more than 104 s was achieved at an elevated measurement temperature. In addition, a stable cycling endurance with the resistance ratio of more than three orders of magnitude of the GdxOy RRAMs can be obtained.

In-Ga-Zn-O (IGZO) was widely applied in the substrate of TFT to replace α-Si in recent years. In this study, IGZO layer with thickness of 70 nm is firstly proposed as a pH-sensing membrane directly deposited on P-type Si substrate acting as an extended gate of conventional extended-gate field-effect transistor (EGFET). Post-deposition rapid thermal anneal (RTA) was performed to improve pH sensing performance of IGZO layer sputtered with Ar/O 2 flow rate of 20/5 in sccm. Sensitivity could be increased from 41.5 mV/pH to 53.3 mV/pH by RTA in N 2 ambience at 700 o C in pH application range between pH 2 and 10. XRD analysis supports the orientation changes of IGZO layer after RTA at different temperature. Ar/O 2 ratio was also modified in the RF sputtering. IGZO-EGFET prepared by Ar/O 2 ambience of 24/1 in sputtering can have the highest sensitivity and linearity of 59.5 mV/pH and 99.7%, respectively. After 7 months, sensitivity and linearity are 51.4 mV/pH and 92%, respectively. Etch rate and drift coefficient in standard buffer solution are higher than in other sensing material for EGFET and ISFET. More studies on enlargement of pH application range and minimisation of non-ideal effect still need to be investigated before real applications.

The effect of nitrogen plasma immersion ion implantation (PIII) treatment on the thin films of gadolinium oxide (Gd x O y ) for use in resistive random access memory (RRAM) applications is reported. From the X-ray photoelectron spectroscopic analysis, the formation of Gd-N bond was evidenced by a shift in the peak Gd 4d peaks towards lower binding energy. It was observed that the nitrogen PIII treatment enhanced the product yield of the Gd x O y RRAM up to 77%. With the nitrogen PIII treatment, the switching mechanism of the Gd x O y RRAMs changed from Schottky emission to space-charge-limited-current conduction, as determined by the current-voltage fitting and device-area-dependent measurements. The nitrogen PIII-treated Gd x O y RRAMs prepared in this study could provide a high resistance ratio of 10 4 , suitable for future application as non-volatile memory.

The characteristics of gadolinium oxide (GdxOy) resistive switching memories (RRAMs) with a Pt–Al alloy (5.88 at% Al) top electrode (TE) and the effect of post-metallization annealing (PMA) were investigated. Resistance of high resistance state increased with increasing PMA temperature, achieving a resistance ratio of more than 104 owing to the increased Schottky barrier height between the TE and GdxOy film. The change in set and reset voltages corresponded to the concentration of oxygen vacancies at the TE/GdxOy interface, which was examined by x-ray photoelectron spectroscopy. At the PMA temperatures for higher than 350 °C, the GdxOy RRAMs with Pt–Al alloy TEs presented superior retention behaviour for more than 104 s at a testing temperature of 130 °C. Al diffusion into the GdxOy film to form AlxOy at the TE/GdxOy interface is responsible for the retention enhancement because it prevented the oxygen ions from out-diffusion through the Pt grain boundaries.

The effects of remote NH3 plasma treatment on a Pt/Gd x O y /W resistive random access memory (RRAM) metal–insulator–metal (MIM) structure were investigated. We found that a decrease in the electron barrier height caused by nitrogen incorporation at the Pt–Gd x O y interface can help reduce the operational set and reset voltages. Nitrogen atoms from the NH3 plasma prevent oxygen atoms in the film from diffusing through Pt grain boundaries into the atmosphere, resulting in superior retention properties (>104 s). The stability of the endurance behavior of Gd x O y RRAMs was significantly improved owing to the passivation of defects in Gd x O y films by nitrogen and hydrogen atoms from the remote NH3 plasma, markedly reducing plasma damage.

In this study, the carrier injection mechanism of gold and gadolinium oxide bi-nanocrystals (BNCs) with hafnium dioxide NC separation layer was investigated. Further, an N-shaped carrier injection curve was observed under positive gate bias. It is resulted from the hybrid polarity and carrier injection. To identify the injection, the activation energies of charge loss were analyzed, and it was found that the substrate-injected electrons and gate-injected holes were stored in the BNCs. The gate-injected carriers were trapped at the Au-NCs and HfO2 interface, exhibiting high-density (>2.45 × 1012 cm−2) and high-speed (∼μs) operation characteristics suitable for future use in flash memories.

A programmable silicon–oxide–nitride–oxide–silicon (SONOS)-like electrolyte–insulator–semiconductor (EIS) sensor with a Sm2O3/Si3N4/SiO2/Si structure is demonstrated for pH detection. This proposed programmable EIS sensor with insulator–nitride–oxide (INO) multiple sensing layers exhibits a high pH sensitivity (larger than the ideal Nernst response, ∼59 mV/pH) owing to the hydrogen ion attraction by electrons trapped within the embedded Si3N4 layer after stressing. To increase the pH response, rapid thermal annealing is performed on the programmable EIS devices. The obtained results support our hypothesis that the pH response can be effectively increased after 700 °C annealing. A sensing model on the basis of the charge attraction and surface roughness is also presented. Compared with the conventional EIS device, the programmable EIS sensor functionalized with annealing and stressing can be used in future pH sensor applications owing to its high pH sensing response.

In this article, thin hafnium oxide (HfO2) films deposited by atomic layer deposition (ALD) were investigated as a sensing layer on an electrolyte–insulator–semiconductor (EIS) structure for pH sensor applications. Compared with sputtering, ALD provides the possibility of shrinking the thickness of the HfO2 sensing layer down to 3.5 nm with a low drift coefficient (2 film. After annealing at 900 °C, the pH sensitivity could be effectively increased to that near the Nernstian response (59.6 mV/pH), and the drift coefficient (2 film is a promising candidate for pH sensor fabrications.

We investigated the effect of the carbon tetrafluoride (CF4) plasma treatment on pH and pNa sensing characteristics of a light-addressable potentiometric sensor (LAPS) with a 2-nm-thick HfO2 film grown by atomic layer deposition (ALD). An inorganic CF4 plasma treatment with different times was performed using plasma enhance chemical vapor deposition (PECVD). For pH detection, the pH sensitivity slightly decreased with increasing CF4 plasma time. For pNa detection, the proposed fluorinated HfO2 film on a LAPS device is sensitive to Na+ ions. The linear relationship between pNa sensitivity and plasma treatment time was observed and the highest pNa sensitivity of 33.9 mV/pNa measured from pNa 1 to pNa 3 was achieved. Compared with that of the same structure without plasma treatment, the sensitivity was improved by twofold. The response mechanism of the fluorinated HfO2 LAPS is discussed according to the chemical states determined by X-ray photoelectron spectroscopy (XPS) analysis. The analysis of F 1s, Hf 4f, and O 1s spectra gives evidence that the enhancement of pNa sensitivity is due to the high concentration of incorporated fluorine in HfO2 films by CF4 plasma surface treatment.

We investigate a reference electrode–insulator–nitride–oxide–semiconductor (RINOS) structure with a Sm2O3 sensing membrane and using silicon nitride as the charge trapping layer for pH detection. The proposed RINOS device with the oxide–nitride–oxide (ONO) structure exhibits a high pH sensitivity (larger than the ideal Nernst response, ∼59 mV/pH) owing to hydrogen ion adsorption by the trapped electrons within the embedded Si3N4 layer when applying a stress voltage. As the applied voltage and time increase, pH sensitivity increased. The possible sensing mechanism based on charge attraction was demonstrated using schematic band diagrams. To improve the retention of an increased sensitivity, an additional SiO2 layer as a blocking layer between the Sm2O3 and Si3N4 films to form the RIONOS device was proposed. Compared with the conventional electrolyte–insulator–semiconductor (EIS) structure, the proposed RIONOS device can be used to detect ultra small pH variations owing to its high pH-sensing response.

The effects of CF4 plasma treatment on Gd2O3 nanocrystal (NC) memory were investigated. For material analysis, secondary ion mass spectrometry and x-ray photoelectron spectroscopy analyses were performed to characterize the fluorine depth profile of the Gd2O3-NC film. In addition, an UV–visible spectrophotometer was used to obtain the Gd2O3 bandgap and analyzed to suggest the modified structure of the energy band. Moreover, the electrical properties, including the memory window, program/erase speed, charge retention, and endurance characteristics were significantly improved depending on the CF4 plasma treatment conditions. This can be explained by the physical model based on the built-in electric field in the Gd2O3 nanostructure. However, it was observed that too much CF4 plasma caused large surface roughness induced by the plasma damage, leading to characteristics degradation. It was concluded that with suitable CF4 plasma treatment, this Gd2O3-NC memory can be applied to future nonvolatile memory applic...

A method to acquire a zero dipole high-k/SiO 2 interface has been proposed. We introduced Gd elements into HfO 2 to compensate the V FB shift cause by interface dipoles with multiple Gd fractions and further inferred a composition of HfGdO gate dielectric layer with no interface dipoles. The physical and electrical results reveal that the band gap, conduction offset, and oxide charges are improved with increased Gd elements. With the extraction of electron effective mass and Schottky barrier of each HfGdO layer, the band structures were established, and the amount of Fermi level pinning and interface dipoles could be successfully quantified and separated by analyzing the dissimilitude of work functions obtained by different extractions. A Hf/Gd dual-sputtered power ratio of 150/43 was interpolated to realize a zero dipole interface.

The charge-trapping layer of HfGdO dielectrics deposited by a dual-sputtered process for a silicon-oxide-nitride-oxide-silicon-type nonvolatile memory application was investigated. Different Ar/O2 flow ratios and Hf/Gd dual-sputtered power ratios were performed and the process sensitivity on the memory characteristics was analyzed. It is observed that the nonstoichiometric GdO (200) structure may be the main charge-trapping site for the HfGdO silicon-oxide-nitride-oxide-silicon-type memories. The memories with Hf/Gd=150/150 and Ar/O2=20/5 exhibit better electrical performance than others and can be applied into future nonvolatile memory.

p-channel metal oxide semiconductor field-effect transistor (pMOSFET) devices with a ternary Hf x Mo y N z metal gate and a Gd2O3 high-k gate dielectric have been demonstrated for the first time. The nitrogen-concentration-control method is a simple and cost-effective technique for metal work-function modulation. Hf x Mo y N z thin films were cosputtered from pure hafnium (Hf) and molybdenum (Mo) targets in nitrogen (N2) and argon (Ar) mixtures. The Hf x Mo y N z thin films have low resistivity and high thermal stability up to 950 °C. The threshold voltage (V th) of the Hf x Mo y N z /Gd2O3 pMOSFET can be tuned from -0.6 to -0.08 V by controlling the nitrogen flow ratio. Moreover, there is little negative bias temperature instability (NBTI) degradation of the Hf x Mo y N z /Gd2O3 pMOSFET device. Compared with the Hf x Mo y N z /SiO2 pMOSFET, the Hf x Mo y N z /Gd2O3 pMOSFET has a small threshold voltage modulation owing to the extrinsic Fermi level effect at the Hf x Mo y N z and Gd2O3 interface. A physical model has been proposed to explain the extrinsic Fermi level pinning effect of the Hf x Mo y N z /Gd2O3 pMOSFET device.

Gadolinium oxide nanocrystal (Gd 2 O 3 -NC) memories treated by postdeposition rapid thermal annealing were investigated. Bandgap offset performed by a crystallized Gd 2 O 3 -NC dot surrounded by amorphous Gd 2 O 3 dielectrics is successfully demonstrated and proven by the transmission electron microscopy images and electron diffraction pattern. The Gd 2 O 3 -NC memory exhibits a hysteresis memory window of 4 V and NC dot density of more than 8.5 X 10 11 cm -2 . In addition, the formation of Gd 2 O 3 -NC and charge loss characteristics on annealing temperature were analyzed and optimized at 850°C. The data endurance of 10 4 program and erase cycling for a sufficient memory window (>2 V) was also observed for the Gd 2 O 3 nanocrystal memory.

In this letter, the effects of pre-CF4 plasma treatment on Si for sputtered HfO2 gate dielectrics are investigated. The significant fluorine was incorporated at the HfO2∕Si substrate interface for a sample with the CF4 plasma pretreatment. The Hf silicide was suppressed and Hf–F bonding was observed for the CF4 plasma pretreated sample. Compared with the as-deposited sample, the effective oxide thickness was much reduced for the pre-CF4 plasma treated sample due to the elimination of the interfacial layer between HfO2 and Si substrate. These improved characteristics of the HfO2 gate dielectrics can be explained in terms of the fluorine atoms blocking oxygen diffusion through the HfO2 film into the Si substrate.

The work function of hafnium (Hf) was modified by nitrogen (N) in dc reactive sputtering. The resistivity of the HfN x thin film is sufficiently low up to the N 2 flow ratio of 10%. In addition, the work function is tuned from conduction band (4.1 eV) to midgap (4.55 eV) with increasing N 2 flow ratio. From the X-ray diffraction data, the HfN(200) peak can be observed from the samples which exceed the 8% N 2 flow ratio, which is responsible for the work function increase of the HfN x film.

In this letter, we reported a high-k gadolinium oxide (Gd2O3) gate dielectric formed by reactive rf sputtering. It is found that the Gd2O3 gate dielectric film exhibits excellent electrical properties such as low leakage current density, high breakdown voltage, and almost no hysteresis and frequency dispersion in C‐V curves comparable to that of HfO2 film. This indicates that postprocessing treatments can reduce a large amount of interface trap and can passivate a large amount of trapped charge at defect sites.

In this paper, fluorine incorporation into the HfO2 gate dielectrics by post CF4 plasma treatment was proposed to improve the electrical characterization. TaN–HfO2–p-Si capacitors were demonstrated in this work. The characteristics of fluorinated HfO2 gate dielectrics were improved, including the capacitance-voltage hysteresis and current-voltage behaviors. This may be attributed to the fluorine incorporated into the HfO2 gate dielectrics as revealed by secondary ion mass spectroscopy. Moreover, the formation of Hf-F bonding was observed through electron spectroscopy for chemical analysis spectra.

In this study, a novel approach was proposed to improve the characterization of HfO2. Fluorine was incorporated by CF4 plasma to improve the HfO2 gate dielectric properties including leakage current, breakdown voltage and hysteresis. The hysteresis of capacitance–voltage characteristics can be reduced to approximately 10% hysteresis voltage for the samples with CF4 plasma treatment. An inner-interface trapping model is presented to explain the hysteresis. The secondary-ion mass spectroscopy (SIMS) results show that there is a significant incorporation of fluorine (F) at the interface between the HfO2 thin film and silicon substrate. The incorporation of F effectively suppressed leakage current and improved carrier trapping without an increase in interfacial layer thickness.

This work demonstrates the improved characteristics of an ultrathin CeO 2 dielectric by using the post-N 2 O plasma treatment with additional rapid thermal N 2 annealing. The CeO 2 after the treatment exhibits superior characteristics such as a small effective oxide thickness (∼2.25 nm), a low leakage current (5.4 × 10 -4 A/cm 2 ), a high breakdown electric field (-24 Mv/cm), a long projected 10 yr lifetime (-12 MV/cm), a small capacitance-voltage hysteresis (25 mV), and a high barrier height for Frenkel-Poole emission (0.55 eV). These good properties are attributed to the nitrogen incorporation into the dielectric to eliminate the traps after annealing. The postnitridation annealing appears to be a very useful treatment for future ultrathin metal-oxide gate dielectrics.

For the first time, the characteristics and temperature dependence of electrical properties for ultrathin HfO 2 gate dielectrics treated in NH 3 plasma after deposition were investigated. After this treatment, significantnitrogen incorporation at the HfO 2 /silicon interface (interfacial layer) was examined by Auger electron spectroscopy. Moreover, the formation of Hf-N bonding and the suppression of Hf-Si bonding were observed from electron spectroscopy for chemical analysis spectra. The activation energy of charge trapping reflected in the current-voltage characteristics was effectively reduced, which led to improved hysteresis and its weaker temperature dependence in HfO 2 gate dielectrics treated in NH 3 plasma.