界面顕微光応答法によるAu/Ni/n型β-Ga₂O₃ショットキー接触の電圧印加時における均一性の2次元その場観察

抄録

We applied scanning internal photoemission microscopy (SIPM) to characterize the uniformity of the Au/Ni/n-type β-Ga₂O₃ Schottky contacts under applied voltage of -126 V for 163 hours continuously. The standard deviation (σ) of the SIPM signal on the whole electrode using blue, bluegreen, green, and red laser beam under non-voltage application were less than 2%, and of the Schottky barrier height (qϕ_B) was 4.46 meV. This value was comparable for the n-SiC, n-GaN, and n-α-Ga₂O₃ Schottky contacts. After 163 h voltage application, the σ of qϕ_B on the entire electrode was 20 meV, and the decrease of the average value from 0.5 h was less than 10 meV. It shows no significant degradation and maintaining high qϕ_B values. We demonstrated that the SIPM method can be used to be in-situ observation for electrical uniformity of the Schottky contacts under applying high voltages.