Schottky-Barrier Model Nonlinear in Surface-State Concentration and Calculation of the I#En Dash#V Characteristics of Diodes Based on SiC and Its Solid Solutions in the Composite Charge-Transport Model

A modified Schottky-barrier model, which is nonlinear in terms of the surface-state concentration and contains a local quasi-Fermi level at the interface induced by excess surface charge, is proposed. Such an approach makes it possible to explain the observed similarity of the I#En Dash#V characteristics of diodes with the Schottky barrier M/(SiC)_1–x(AlN)_x and those of heterojunctions based on SiC and its solid solutions taking into account Φ_g ≈ Φ_B. The results of calculations of the Schottky-barrier heights are consistent with the experimental data obtained from measurements of the photocurrent for metals (M): Al, Ti, Cr, and Ni. The I#En Dash#V characteristics in the composite–additive model of charge transport agree with the experimental data for the n-M/p-(SiC)_1–x(AlN)_x and n-6H-SiC/p-(SiC)_0.85(AlN)_0.15 systems.