Insight into Al2O3/ B-doped diamond interface states with high-temperature conductance method

We employed a high temperature conductance method to investigate the interface state properties of the Al2O3/B-doped diamond MOS structure by considering the surface potential fluctuation. Based on Gaussian approximation of Nicollian's model and Brew's graphical approach, we analyzed the frequency dependent characteristics of parallel conductance (Gp/o-f) at various gate voltages and extracted the energy distribution of interface state density (Dit), capture cross section (s p), time constant (sit), and the standard deviation of surface potential fluctuation (s s). The Dit extracted by the conductance method exhibited good agreement with that by the high-low method, whereas there exist large errors when surface potential fluctuation was not considered by using the conductance method. The capture cross section extracted by the conductance method was on the order of 10¹7 cm². From the energy dependence of the interface state time constant, the hole capture and emission follow the Shockley-Read-Hall statistics. s s decreases with the energy position away from the valence band edge (Ev) of diamond, indicating that donor-like traps are distributed in the Ev side of diamond.