Single β-Ga₂O₃ nanowire back-gate field-effect transistor

Abstract

In this work, a normally-on single monocrystal β-Ga2O3 nanowire (NW) back-gate field-effect transistor (FET) has been demonstrated by transferring MOCVD-grown β-Ga2O3 NWs on sapphire onto SiO2(300nm)/p+-Si substrate. When the gate voltage (VG) exceeds -14 V, the device is pinched off, with an on/off ratio greater than 10^8 and a drain leakage current density as low as ~7.34 fA. The maximum field-effect carrier mobility for these n-doped single β-Ga2O3 NW FETs reaches ~62.2 cm2/V·s. A prompt degradation in the on/off ratio for these β-Ga2O3 NW back-gate FETs is observed as the operation temperature increased up to 400 K. With strong evidence, the temperature-dependent degradation in the performance is determined by the activation of self-trapped holes and intrinsic vacancies related defects, both of which would lead to a rapid increase in the channel leakage current at high temperatures.

Effects of Annealing on Surface Residual Impurities and Intrinsic Defects of β-Ga2O3

“…β-Ga 2 O 3 shows a large bandgap (4.5-4.9 eV) and high breakdown electric field (~8 MV/cm) to produce a Baliga's figure of merit (BFOM) over 3000, which is much higher than SiC BFOM and GaN BFOM. As a result, β-Ga 2 O 3 is superior in power device applications, the performance of which can be conveniently modulated due to its good n-type doping controllability over a wide range of 10 15 -10 19 cm −3 [2][3][4][5]. Based on its ultra-wide bandgap, β-Ga 2 O 3 also demonstrates the exclusive potential for use in optoelectronic detection for solar-blind wavelength (<280 nm), which matches its bandgap well.…”

One-Step Preparation of Si-Doped Ultra-Long β-Ga2O3 Nanowires by Low-Pressure Chemical Vapor Deposition

“…β-Ga 2 O 3 has been emerging an important wide bandgap (4.9 eV) semiconductor material [1][2][3][4][5][6], and has attracted much attention with its outstanding properties, including high breakdown field (~8 MV/cm) [7,8], high Baliga's figure of merit, which is 10 and 4 times higher than that of SiC and GaN [9,10], and thermal and mechanical stability [11][12][13][14]. These allow β-Ga 2 O 3 to be used in high-power, solar-blind ultraviolet photodetectors, and gas sensors [15,16].…”

“…Compared to film and buck β-Ga 2 O 3 , the controllable growth of β-Ga 2 O 3 nanowires is interesting, due to the fact that one-dimensional (1D) circular β-Ga 2 O 3 nanowires (NWs) offer an option to be used as conducting channels, thus achieving further scaling down and ultra-compact electronic integration [24]. For example, Guangming Qu et al [7] fabricate field-effect transistors (FET) with a back-gate structure, based on β-Ga 2 O 3 nanowires transferred to silicon substrate, which has a layer of naturally oxidized silicon oxide on the surface. The switching ratio of the device exceeds 10 8 , and the leakage current is only 7.34 fA.…”