Electrical properties and the determination of interface state density from I-V, C-f and G-f measurements in Ir/Ru/n-InGaN Schottky barrier diode

Abstract

The electrical properties of the Ir/Ru Schottky contacts on n-InGaN have been investigated by current-voltage (I-V), capacitance-voltage (C-V), capacitance-frequency (C-f) and conductance-frequency (G-f) measurements. The obtained mean barrier height and ideality factor from I-V are 0.61 eV and 1.89. The built-in potential, doping concentration and barrier height values are also estimated from the C-V measurements and the corresponding values are 0.62 V, 1.20x1017 cm-3 and 0.79 eV, respectively. The interface state density (NSS) obtained from forward bias I-V characteristics by considering the series resistance (RS) values are lower without considering the series resistance (RS). Furthermore, the interface state density (NSS) and relaxation time (tau) are also calculated from the experimental C-f and G-f measurements. The NSS values obtained from the I-V characteristics are almost three orders higher than the NSS values obtained from the C-f and G-f measurements. The experimental results depict that NSS and tau are decreased with bias voltage. The frequency dependence of the series resistance (RS) is attributed to the particular distribution density of interface states. DOI: 10.21883/FTP.2017.12.45189.8340