Leakage current conduction mechanisms and electrical properties of atomic-layer-deposited HfO₂/Ga₂O₃ MOS capacitors

Abstract

In this paper, current conduction mechanisms in HfO2/β-Ga2O3 metal–oxide–semiconductor (MOS) capacitors under positive and negative biases are investigated using the current–voltage (I–V) measurements conducted at temperatures from 298 K to 378 K. The Schottky emission is dominant under positively biased electric fields of 0.37–2.19 MV cm−1, and the extracted Schottky barrier height ranged from 0.88 eV to 0.91 eV at various temperatures. The Poole–Frenkel emission dominates under negatively biased fields of 1.92–4.83 MV cm−1, and the trap energy levels are from 0.71 eV to 0.77 eV at various temperatures. The conduction band offset (ΔEc) of HfO2/β-Ga2O3 is extracted to be 1.31 ± 0.05 eV via x-ray photoelectron spectroscopy, while a large negative sheet charge density of 1.04 × 1013 cm−2 is induced at the oxide layer and/or HfO2/β-Ga2O3 interface. A low C–V hysteresis of 0.76 V, low interface state density (Dit) close to 1 × 1012 eV−1 cm−2, and low leakage current density of 2.38 × 10−5 A cm−2 at a gate voltage of 7 V has been obtained, suggesting the great electrical properties of HfO2/β-Ga2O3 MOSCAP. According to the above analysis, ALD-HfO2 is an attractive candidate for high voltage β-Ga2O3 power devices.

Stress-induced charge trapping and electrical properties of atomic-layer-deposited HfAlO/Ga2O3 metal–oxide–semiconductor capacitors

“…• cm -2 , using the single frequency method [26] , by equation ( 3)) of HfAlO/Ga2O3 interface approve the above speculation. Between SiO2/Ga2O3 [27] , Al2O3/Ga2O3 [13] , and HfO2/Ga2O3 [16,22] interface, a large number of fixed sheet charges were also found, and the calculated Neff on the HfAlO/Ga2O3 interface is close to reported values (SiO2/Ga2O3: 5.5 × 10 12 cm -2 [27] , Al2O3/Ga2O3: 3.6 × 10 12 cm -2 [13] , respectively). We speculate that the interface traps may possible act as acceptor states during the formation of negative fixed charges, similar with HfO2/Ga2O3 [16] .…”

“…Understanding the electrical properties of the oxide-Ga2O3 interfaces under either normal condition or constant voltage stress is important for developing Ga2O3 MOS devices, which impact critical parameters such as threshold voltage, channel mobility, and device stability. Analyses of the interface state density at the interface between β-Ga2O3 and atomic layer deposition (ALD) or Low-Pressure Chemical Vapor Deposition (LPCVD) SiO2 [19,20] , ALD Al2O3 [13,19,21] , and ALD HfO2 [16,22] dielectrics have been reported recently, particularly, there are already many systematical works [13,19,21] about the electrical properties, interface trap, and stress-induced charge trapping of the Al2O3/β-Ga2O3 MOS structures, but only a few work [21] focus on stress-induced reliability of the β-Ga2O3 MOS capacitor. In this work, β-Ga2O3 MOS capacitors (MOSCAP) with ALD-derived HfAlO dielectric were fabricated, and the responses to constant voltage stress (CVS) of HfAlO /Ga2O3 MOS structure were evaluated via capacitance-voltage (C-V) and current-voltage (I-V) methods.…”

β-Ga2O3 nanorod arrays with high light-to-electron conversion for solar-blind deep ultraviolet photodetection

“…Among all ve phases of Ga 2 O 3 (a, b, g, d and 3), the b-Ga 2 O 3 with monoclinic crystal structure is the thermally and chemically most stable phase, has been widely studied in solar-blind photodetectors. [13][14][15][16][17][18][19] So far, b-Ga 2 O 3 -based photodetectors mainly fall into three categories: lm type, single crystals and nanorod arrays (NRAs) type. Compared to thin lms, vertical nanowire array structures display more superior optical absorption ability and higher carrier generation, resulting from high surface-to-volume ratio and effective optical coupling, which can further improve the performance of photodetectors.…”

Interface chemistry modulation and dielectric optimization of TMA-passivated HfDyOx/Ge gate stacks using doping concentration and thermal treatment

“…In addition, based on the linear tting lines slope ¼ 1 kT can be extracted and are exhibited inFig. 12 32,33. It can be noted that the values of 3…”