Study of the characteristics current-voltage and capacitance-voltage in nitride GaAs Schottky diode

Abstract

This article reports the study of Au/GaN/GaAs Schottky diodes, where the thin GaN film is prepared by nitridation of GaAs substrates with thicknesses of 0.7 and 0.8 nm. The resulting GaN sample with thickness 0.8 nm is then treated with an annealing operation (heating to 620 °C) to improve the current transport. The current-voltage ( I-V ) and capacitance-voltage ( C-V ) of the Au/GaN/GaAs structures were investigated at room temperature. In fact, the I-V characteristics show that the annealed sample has low series resistance ( R s ) and ideality factor ( n ) (63 Ω, 2.27 respectively) when compared to the values obtained in the untreated sample (1.83 kΩ, 3.31 respectively). The formation of the GaN layer on the gallium arsenide surface is investigated through calculation of the interface state density N SS with and without the presence of series resistance R s . The value of the interface state density N SS ( E ) close to the mid-gap was estimated to be in the order of 4.7×10 12 cm -2 eV -1 and 1.02× 10 13 cm -2 eV -1 with and without the annealing operation, respectively. However, nitridation with the annealing operation at 620 °C improves the electrical properties of the resultant Schottky diode.