Low Leakage Current Density Research Articles

Scalable all polymer dielectrics with self-assembled nanoscale multiboundary exhibiting superior high temperature capacitive performance

Polymers are key dielectric materials for energy storage capacitors in advanced electronics and electric power systems due to their high breakdown strengths, low loss, great reliability, lightweight, and low cost. However, their electric and dielectric performance deteriorates at elevated temperatures, making them unable to meet the rising demand for harsh-environment electronics such as electric vehicles, renewable energy, and electrified transportation. Here, we present an all-polymer nanostructured dielectric material that achieves a discharged energy density of 7.1 J/cm³ with a charge-discharge efficiency of 90% at 150°C, outperforming the existing dielectric polymers and representing more than a twofold improvement in discharged energy density compared with polyetherimide. The self-assembled nano-scale multiboundaries effectively impede the charge injection and excitation, leading to more than one order of magnitude lower leakage current density than the pristine polymer matrix PEI at high electric fields and elevated temperature. In addition, the film processing is simple, straightforward, and low cost, thus this all-polymer nanostructured dielectric material strategy is suitable for the mass production of dielectric polymer films for high-temperature capacitive energy storage.

Structural and electrical characterization of phase evolution in epitaxial Gd2O3 due to anneal temperature for silicon on insulator application

In this work, we understand the post-deposition anneal temperature effects on structural and electrical (leakage current and trap density) properties of epitaxial Gd2O3 film grown on Si (111) substrate using a cost-effective and High-Volume Manufacturing capable radio frequency sputtering method. It is found that the Rapid Thermal Annealing (RTA) at an optimum temperature of 850 °C enhances the crystallinity of the cubic phase in film. However, at higher RTA temperatures (>900 °C to 1050 °C), Si out-diffusion in Gd2O3 film is manifested as the reason for phase evolution towards the amorphous phase. The electrical characterization shows the film's low leakage current density of 100 nA/cm2. Moreover, increased breakdown voltage and field are observed with increasing RTA temperature. The frequency-dependent Capacitance-Voltage analysis shows a parallel shift accompanied by a kink at a lower frequency, indicating the presence of interface traps (Dit) with a range of time constants. After the forming gas annealing, a significant reduction in Dit is observed. The low leakage current density, low Dit and high crystallinity make Gd2O3 a promising candidate as a buried oxide in Silicon on Insulator MOSFETs.

Enhanced Oxidation Resistance and Interface Stability of Atomic-Layer-Deposited MoNx Electrodes via TiN Passivation for DRAM Cell Capacitor Applications.

The continuous miniaturization of dynamic random-access memory (DRAM) capacitors has amplified the demand for electrode materials featuring specific characteristics, such as low resistivity, high work function, chemical stability, excellent interface quality with high-k dielectrics, and superior mechanical properties. In this study, molybdenum nitride (MoNx) films were deposited using a plasma-enhanced atomic layer deposition (PEALD) employing bis(isopropylcyclopentadienyl)molybdenum(IV) dihydride and NH3 plasma for DRAM capacitor electrode applications. Depending on the deposition temperatures of the PEALD MoNx films ranging from 200 to 400 °C, the Mo/N ratio and crystal structure varied, transitioning from the cubic NaCl-B1-type MoN phase with Mo/N ratio of 1.4 to the cubic γ-Mo2N phase with Mo/N ratio of 1.9. Notably, MoNx films grown at 400 °C exhibited low resistivity (435 μΩ·cm), a high work function (5.28 eV), and superior mechanical hardness (11.3 GPa) compared to ALD TiN films. Despite these excellent properties, the PEALD MoNx electrode demonstrated insufficient chemical stability, particularly in terms of oxidation resistance and interface quality with ALD HfxZr1-xO2 (HZO) films. This resulted in poor morphology and the formation of significant oxygen-deficient HZO layers (such as HfO2-x), leading to considerable degradation in the electrical performance of metal-insulator-metal (MIM) capacitors. To mitigate this issue, a thin (2.5-14 nm) ALD TiN layer was introduced as a passivation layer between the MoNx bottom electrode and HZO dielectric. The TiN-passivated MoNx (TiN/MoNx) electrode showed substantially enhanced oxidation resistance and reduced interfacial reactions with the HZO dielectric. Consequently, MIM capacitors with TiN/MoNx bottom electrodes demonstrated outstanding electrical performance, including excellent dielectric properties, low leakage current density, and high mechanical strength. Hence, this study proposes a promising candidates for storage nodes in the next-generation DRAM capacitors.

MIM Capacitors Featuring Low EOT and Low Leakage Current Density by Nitrogen-Incorporated HfO₂/ZrO₂/HfO₂

MIM Capacitors Featuring Low EOT and Low Leakage Current Density by Nitrogen-Incorporated HfO₂/ZrO₂/HfO₂

Effects of sintering temperature on microstructure and varistor performances of ZnO-SrCO3-Co2O3 ceramics

Sintering temperature is decisive for optimizing the grain boundary environment to obtain the high performance ZnO based varistor ceramic. In this work, the impacts of sintering temperature on microstructure and electrical properties of ternary Zn-Sr-Co varistor were investigated. It was found that the distribution of Sr, the critical factor to form grain boundary, was heavily sensitive to sintering temperature. The considerable Sr ions precipitated at grain boundaries and formed the clusters of SrZnO2 while the sintering temperature increases from 1150 °C to 1190 °C. Besides, the precipitation of Sr led to the large segregation of Co at grain boundaries. The enrichment behavior of Sr and Co contributed to the optimization of grain boundaries, resulting in the enhanced barrier height. As a result, the excellent nonlinear current-voltage performances, i.e., the high nonlinear coefficient of 56.47 and the low leakage current density of 0.73 μA/cm2 were obtained in the ternary ZnO-SrCO3-Co2O3 varistor sintered at 1190 °C. However, the grain boundary environment would be destroyed by the excessive temperature of 1210 °C, resulting in the degradation of grain boundary barrier and especially a surge in the leakage current IL from 0.73 to 92.19 μA/cm2. In addition, varying sintering temperature has the important effects on impedance and dielectric properties of the ZnO-SrCO3-Co2O3 varistors. The findings provide new perspectives for developing the high-performance ternary ZnO-SrCO3-Co2O3 varistor ceramics by optimizing the initial grain boundary environment at different sintering temperatures.

Promising ferroelectric and piezoelectric response of Cr-doped ZnO nanofiller-incorporated PVDF flexible and laminated nanocomposite system.

Cr3+-doped ZnO (CZ) nanoparticles are prepared using hydrothermal and co-precipitation techniques. The desired crystallographic phase of the nanoparticles is confirmed using X-ray diffraction study. Rod-shaped and spherical morphologies of CZ nanoparticles prepared using hydrothermal and co-precipitation techniques were confirmed through FESEM observation. Each type of nanoparticle was taken separately in PVDF to understand the characteristic properties, such as dielectric, piezoelectric, and ferroelectric properties of the resultant CZ-PVDF nanocomposite films. All the nanocomposite films comprising rod-shaped or spherical CZ nanoparticles show butterfly loops with a low leakage current density of 10-5 A m-2 at a maximum electric field of 100 kV m-2 under J-E measurement. These findings suggest that the polarization property of CZ-PVDF nanocomposite films can be obtained at a high external electric field without causing electric breakdown in the samples. Dielectric permittivity as a function of temperature increases with an increase in the loading percentage of both rod-shaped or spherical CZ nanofillers in PVDF. Polarization response also improves with an increase in the loading percentage of CZ nanofillers in PVDF. In particular, the rod-shaped CZ nanofillers in PVDF with a higher loading percentage (CZHP2) result in a maximum polarization of (10 ± 0.29) × 10-4 μC cm-2, remanent polarization of (2 ± 0.04) × 10-4 μC cm-2, and coercive field of (10 ± 0.1) kV cm-1 at a maximum electric field of 50 kV cm-1. The CZHP2 nanocomposite film has a piezoelectric coefficient (d33) of (25 ± 0.24) pC N-1 and a power density of 1278.90 W m-3. These results indicate that the nanocomposite films have potential application in piezoelectric energy harvesters, offering a possible solution to the energy issue faced by modern society.

Remote vapor-phase dual alkali halide salts assisted quasi-van der Waals epitaxy of m-phase ZrO2 thin films with high dielectric constant and stable flexible properties

High-κ dielectric constant and wideband gap of ZrO2 material render it as an excellent candidate for transistor gate dielectric layers. However, current reported synthesis techniques suffer the problems of high precursor volatilization rate, ultrasmall grains with low dielectric constant, and high leakage current, which largely impede its application in electronic devices. Here, the quasi-van der Waals epitaxy growth of compact m-phase ZrO2 thin films has been developed, in which the stable supply of Zr source is realized by the tuned sublimation of ZrC powder with remote vapor-phase dual halide salts assistant. The formation of m-phase ZrO2 is due to the lower Gibbs free energy, in which the crystal nucleates at the etched hole edges of mica substrate, thus forming hexagonal shape polycrystal grains and merging as the continuous thin films. The microstructures and Raman spectrum characterization reveal the two dominated growth orientations and good crystal qualities, which indicate the uniform dielectric constant. The excellent growth reproducibility could be easily adapted to thin metal substrates, such as tungsten, molybdenum, and stainless steel, where the adhesion strength is strong because of the higher density of interfacial chemical bonding. Meanwhile, the metal–insulator–metal flexible capacitors show the high dielectric constant of 23–26 and low leakage current density of 10−4 A/cm2 at large voltage and only exhibit the decreased capacitance density of 7% after several hundred bending cycles. Our work paves a way to achieve the high-quality dielectric thin films on various substrates by the unique chemical vapor deposition design strategy.

Alpha particle detection based on low leakage and high-barrier vertical PtOx/β-Ga2O3 Schottky barrier diode

High-performance radiation detectors are essential in many sectors spanning medical diagnostics, nuclear control, and particle physics. Ultrawide bandgap semiconductor materials have become one of the most promising candidates due to their excellent performance. Here, based on β-Ga2O3, a Schottky diode-type alpha particle detector was demonstrated. In order to reduce the reverse leakage current of the large-area device, the metal-oxide electrode PtOx was introduced to form high-barrier contacts (1.83 eV) with Ga2O3. The device exhibits a low leakage current density of 63 pA/cm2 at −100 V and apparent energy spectra of 241Am generated alpha particles with an energy of 5.486 MeV at various reverse voltages from −40 to −120 V. The charge collection efficiency (CCE) and energy resolution of the device (at −120 V) are 31.7% and 15.3%, respectively. Meanwhile, the mechanism of interaction between alpha particles and β-Ga2O3 was analyzed, and a 45° oblique incidence was adopted to increase the deposited energy of alpha particles in the depletion region. Furthermore, the differences between actual CCE and theoretical CCE are investigated as guidance for further improving detector performance. This work reveals the great potential and good prospects of Ga2O3 as an economical, efficient, and radiation-resistant ionizing radiation detector.

High-Performance TiO2/ZrO2/TiO2 Thin Film Capacitor by Plasma-Assisted Atomic Layer Annealing.

Although laminate structures are widely used in electrostatic capacitors, unavoidable heterogeneous interfaces often deteriorate the dielectric properties by impeding film crystallization. In this study, a TiO2/ZrO2/TiO2 (TZT) laminate structure, where upper-TiO2 deposited on the heterogeneous interface was crystallized by plasma-assisted atomic layer annealing (ALA), was investigated. ALA effectively induced the phase transition of the upper-TiO2 from the amorphous or anatase phase to the rutile phase, leading to an increase in the dielectric constant, whereas the ZrO2 blocking interlayer maintained the amorphous phase owing to the extremely localized effect of ALA. Consequently, through the layer-by-layer phase control of ALA, the dielectric constant of the upper-TiO2 was enhanced by 25% by applying ALA, leading to an increase in a capacitance density of 27% of the TZT capacitor, whereas a low leakage current density of ∼10-8 A/cm2 was maintained (at 1 V). In addition, the TZT capacitor on three-dimensional structures (aspect ratio of 5:1) shows a high capacitance density of up to 461 nF/mm2 owing to ALA.

Efficient gradient heating-up approach for rapid growth of high-quality amorphous ZrO2 dielectric films

High-k oxide dielectric films are indispensable for low-power-consumption oxide thin-film transistors (TFTs) applied in advanced and portable electronics. However, high-quality oxide dielectric films prepared by solution process typically require sophisticated processes and long thermal annealing time, severely limiting both the throughput manufacturing and cost-effectiveness. In this study, the influence of different heating-up methods on the surface morphology and dielectric properties was systematically investigated. Gradient heating-up method could not only substantially improve the surface morphology and quality of high-k ZrO2 films but also efficiently shorten the annealing time. The gradient heating-up process was further designed on the basis of thermal behavior of the xerogel-like precursor, which successfully realize the preparation of high-quality ZrO2 films with an annealing time of 5 min (i.e. the efficiency of thermal treatment increased by about 89%). The ZrO2 film presented excellent dielectric properties, including a low leakage current density of ∼10−8 A cm−2 (at 2 MV cm−1 ), a large areal capacitance of 169 nF cm−2 and a high dielectric constant of 20.41 (1 MHz). Furthermore, InSnZnO TFT based on the ZrO2 gate dielectrics shows an acceptable device performances, such as a high carrier mobility of 2.82 cm2 V−1 s, a high on/off current ratio of ∼105 and a low subthreshold swing of 0.19 V decade −1 at a low operation voltage of 5 V. This work provide a highly promising approach to fabricate high-quality solution-processed high-k oxide dielectric films employed for large-scale and low-power-consumption electronics.

High performance Bi–Co–Mn–Si–B-doped ZnO varistors with wide ranging breakdown voltage and high resistance to electrical degradation

A simple ZnO varistor with high resistance to electrical degradation and an adjustable breakdown voltage range of 100–3000 V/mm was developed by adding SiO2 and B2O3 to Bi–Mn–Co-doped ZnO. Samples were fabricated by sintering at 1150 ºC and doped with 0–55 mol% SiO2 to adjust breakdown voltage. High nonlinear index and low leakage current density were confirmed with addition of SiO2; however, severe electrical degradation occurred. Addition of 1 mol% B2O3 successfully improved the resistance to electrical degradation and long-term reliability, due to the formation of homogenous glass-phase Bi–B–O at grain boundaries inhibiting ion migration. A stabilized interface trap with ∼0.6 eV and 10−21 (m2) was found in samples with 1 mol% B2O3.

Electrical characteristics and trap signatures for Schottky barrier diodes on 4H-SiC, GaN-on-GaN, AlGaN/GaN epitaxial substrates

The forward and reverse current transport mechanisms, temperature dependence of Schottky barrier height (SBH) and ideality factor, barrier inhomogeneity analysis, and trap parameters for Schottky barrier diodes (SBDs) fabricated on 4H-SiC, GaN-on-GaN and AlGaN/GaN epitaxial substrates are reported. High SBH is identified for Ni/4H-SiC (1.31 eV) and Ti/4H-SiC (1.18 eV) SBDs with a low leakage current density of <10−8 A cm−2 at −200 V. Thermally stimulated capacitance detects the well-known Z1/2 electron trap at E C—0.65 eV in both 4H-SiC SBDs, while an additional deep-level trap at E C—1.13 eV is found only in Ni/4H-SiC SBDs. The vertical Ni/GaN SBD exhibits a promising SBH of 0.83 eV, and two electron traps at E C—0.18 eV and E C—0.56 eV are identified from deep-level transient Fourier spectroscopy. A peculiar two-diode model behavior is detected at metal/GaN/AlGaN/GaN interface of high-electron mobility transistor (HEMT); the first diode (SBH-1 of 1.15 eV) exists at the standard Metal/GaN Schottky junction, whereas the second diode (SBH-2 of 0.72 eV) forms due to the energy difference between the AlGaN conduction band and the heterojunction Fermi level. The compensational Fe-doping-related buffer traps at E C—0.5 eV and E C—0.6 eV are determined in the AlGaN/GaN HEMT, through the drain current transient spectroscopy experiments.

Electrical Properties of Laser Patterned Schottky Diode with ALD-Grown TiO2 Interlayer.

Heterojunction formation is the key to adjusting the electronic and optoelectronic properties of various semiconductor devices. There have been various reports on the formation and importance of semiconducting heterojunction devices based on metal oxides. Titanium dioxide (TiO2) is one of the metal oxides that has many unique properties. TiO2's importance is due to its physical and chemical properties such as large band gap, large permittivity, stability, and low leakage current density. In this context, we present the electrical properties of the metal-insulator-semiconductor (MIS) type-TiO2-based Schottky barrier diode (SBD) in the study. To create a thin layer of TiO2 on p-type silicon (p-type Si) patterned partially by the laser-induced periodic surface structure (LIPSS) technique, an atomic layer deposition (ALD) technique was used in the study. For comparison, the current-voltage (I-V) characteristics of the TiO2-based laser-patterned (LP) and nonlaser-patterned (non-LP) diodes were measured at 300 K and in the dark at ±5 V. Classical thermionic emission (TE) theory and Cheung functions were used to investigate the critical diode parameters of the diodes, including ideality factor (n), series resistance (Rs), and barrier height (Φb). The n values were obtained as 4.10 and 3.68 from the TE method and Cheung functions for the LP diode, respectively. The Φb values were found as 0.68 and 0.69 eV from the TE method and Cheung functions, respectively. According to experimental results, the laser patterning resulted in an increase in the Φb values and a decrease in the n values. After laser patterning, it was observed that the device worked effectively, and the ideality factor and barrier height values were improved. This study provides insight into the fabrication and electrical properties of TiO2-based heterojunction devices.

Atomic layer deposition of Y2O3 as high-k dielectrics by using a heteroleptic yttrium precursor and water

Atomic layer deposition (ALD) of Y2O3 thin films was performed on Si substrate by pulsing an unconventional heteroleptic yttrium precursor Y(MeCp)2(Me2Pz) and H2O alternatively. The thin film grew 0.26–0.28 Å per cycle at relatively low temperature of 195–225 °C in a self-limiting manner with negligible nucleation delay, and is close to stoichiometric (O/Y = 1.48, C, 2.56 at%; N, 1.81 at%) in as-deposited form. Integration of the post-annealed ALD Y2O3 film in a metal oxide semiconductor (MOS) capacitor structure exhibits representative electrical properties including a high dielectric constant k of 11.4, high electrical breakdown field of 6.1 MV cm−1 and low leakage current density of 9.1 × 10−8 A cm−2 at − 2 MV cm−1.

Novel high-voltage GaN CAVET with high threshold voltage and low reverse conduction loss

A novel GaN current-aperture vertical electron transistor (CAVET) with an energy band pinning (EBP) structure (EBP-CAVET) is proposed and investigated by simulations. The EBP-CAVET is featured with hybrid contacts on the p-GaN layer, locally having Ohmic contact combined with Schottky gate metals in the longitudinal direction. The Ohmic contact is shorted to the source electrode and the Schottky gate metals are shorted to the gate electrode. The conduction band (Ec) in the gate region is modulated by the alternately arranged contacts. In the Ohmic contact region, Ec remains a fixed value, which acts as an energy band pinning and suppresses the variation of the Ec in the gate region. In the on-state (VGS > 0 V) and blocking-state with high VDS, the EBP structure inhibits the Ec shifting downwards in the gate region to achieve a high threshold voltage (Vth), a low leakage current density (Jdss), and a high breakdown voltage (BV). In the reverse conduction state (VDS < 0 V &VGS ≤ 0 V), the EBP structure suppresses the Ec shifting upwards to achieve a low and independent of gate bias reverse turn-on voltage (VRT). The proposed EBP-CAVET achieves a high Vth of 2.10 V, a VRT of 0.69 V, a low Jdss of 3.1 × 10−11 A/cm2 at VDS = 1000 V, a high BV of 1660 V. Compared with an integrated Schottky barrier diode or fin diode in a field effect transistor (FET), the EBP structure occupies a much smaller chip area. Thus, the EBP-CAVET achieves a low specific ON-resistance (Ron,sp) of 1.19 mΩ cm2 and an extremely high power-figure-of-merit (PFOM) up to 2.32 GW/cm2. Consequently, the proposed structure presents a new design concept and enhances the application potential for GaN CAVET with high Vth and low reverse conduction loss.

P‐7.22: Pulsed laser deposition of wide‐band gap and low leakage current density hafnium oxide thin films

P‐7.22: Pulsed laser deposition of wide‐band gap and low leakage current density hafnium oxide thin films

Performance of normally off hydrogen-terminated diamond field-effect transistor with Al2O3/CeB6 gate materials

In this work, we demonstrate a hydrogen-terminated diamond (H-diamond) field-effect transistor (FET) with Al2O3/CeB6 gate materials. The CeB6 and Al2O3 films have been deposited by electron beam evaporation technique, sequentially. For the 4/8/12/15 μm gate length (LG) devices, the whole devices demonstrate distinct p-type normally off characteristics, and all the threshold voltage are negative; all the absolute values of leakage current density are 10−4 A/cm2 at a VGS of −11 V, exhibiting a relatively low leakage current density compared with CeB6 FETs, and this further demonstrates the feasibility of the introduction of Al2O3 to reduce the leakage current density; the maximum drain–source current density is −114.6, −96.0, −80.9, and −73.7 mA/mm, which may be benefited from the well-protected channel. For the 12 μm LG devices, the saturation carrier mobility is 593.6 cm2/V s, demonstrating a good channel transport characteristic. This work may provide a promising strategy for the application of normally off H-diamond FETs significantly.

Influence of ZnSb2O6 Doping on Phase, Electrical and Dielectric Properties of ZnO Varistors

AbstractThe present investigation reports the variations of the microstructure and electrical properties due to a change in the ZnSb2O6 content of ZnO varistors. The impact of the ZnSb2O6 additive on both microstructure and electrical properties in ZnO varistors is studied via the X‐ray diffraction (XRD) and an impedance analyzer. Zn7Sb2O12 spinel phase and single hexagonal ZnO phase are detected in ZnO varistors with the addition of ZnSb2O6. The ZnO varistors with 5 mol% ZnSb2O6 have the highest nonlinear coefficient (43.2) and the lowest leakage current density (3.96 A cm−2). The resistivity of grain boundary ρgb increases continuously with the increasing content of ZnSb2O6 as demonstrated by impedance measurements. Additionally, low values of dielectric loss at high frequencies suggest a ZnO varistor doped with ZnSb2O6 is suitable for high frequency device applications.

Fabrication of the low-k films with tunable k value as spacers in advanced CMOS technology

In advanced CMOS technology, a suitable spacer scheme is crucial to alleviate the effects of increasing parasitic resistance and capacitance on device performance as the critical dimensions shrinking. Low dielectric constant (low-k) films, possessing a tunable k value ranging from 3.5 to 6.5, were fabricated using plasma-enhanced atomic layer deposition in a single chamber. The fabrication process involved the deposition of the SiN film via SiH2I2 with N2 plasma, as well as the deposition of the SiOX, SiOCN, and SiON films using diisopropylamino silane with O2, Ar/O2, and N2/O2 plasmas, respectively. The introduction of groups containing carbon (C) tended to loosen the film structure, due to its weak bond strength with Si, thus made distinctions in structural and electrical stability. We developed such a process which can adjust the C-group concentration and O, N content to tune the film k value. The SiOx, SiOCN, SiON, and SiN films had high breakdown strength of 9.04, 7.23, 9.41, and over 11 MV cm−1, and meanwhile low leakage current density of 2.42 × 10−9, 4.78 × 10−8, 1.29 × 10−9, and 9.26 × 10−10 A cm−2, respectively. The films exhibited remarkable thermal stability, enhanced breakdown strength, and suppressed leakage with annealing treatment, which could be attributed to the desorption of —CHX groups. Moreover, the low-k materials demonstrated excellent step coverage both in the inner-spacer cavity and on sidewalls, exploring the potential application as spacers in advanced CMOS structure.

Effects of O2/Ar Ratio on Preparation and Dielectric Properties of CaZrO3 Films by Radio Frequency (RF) Magnetron Sputtering.

CaZrO3 (CZO) thin films were deposited on Pt/Ti/SiO2/Si substrates at 450 °C by radio-frequency magnetron sputtering technology. The microstructures and dielectric properties of CZO thin films were investigated. X-ray diffraction analysis reveals that the perovskite orthogonal CZO phase would be promoted by a higher O2 partial pressure in the flow ratio of O2/Ar after thin films were annealed at 700 °C for 3 h in air. The films prepared under the flow ratio of O2/Ar (20:40, 30:40 and 40:40) show the main perovskite crystal phase of CaZrO3 with a small amount of Ca0.2Zr0.8O1.8. The main crystal phase was Ca0.2Zr0.8O1.8 when the film was deposited under an O2/Ar ratio of 40:10. The annealed film with a 40:40 O2/Ar ratio exhibits a dielectric performance with a high dielectric constant (εr) of 25 at 1 MHz, a temperature coefficient of permittivity of not more than 122.7 ppm/°C from 0 °C to 125 °C, and a low leakage current density of about 2 × 10-7 A/cm2 at 30 V with an ohmic conduction mechanism.