C-V and G-V Characteristics of Nitridated GaAs (100) Structures as Function of Frequency-Effect of Series Resistance

Abstract

Different works show that the nitridation of the GaAs surface improves the electrical quality of the Schottky diodes based on gallium arsenic. In order to observe this improvement, capacitance/conductance – voltage characteristics were watched at three frequencies (50, 100 and 500 kHz). These characteristics were corrected by eliminating the effect of the series resistance. First, values of the series resistance were determined and plotted at different frequencies. Rs versus voltage curves show significant values of the series resistance. A peak was observed in these curves at about -0.5 V for the 50 and 100 kHz frequencies and at 0.25 V for the 500 kHz. These peaks are caused by the ohmic back contact and the surface states density. Then the real electrical parameters of the fabricated Schottky diode were calculated and the surface states density of the Schottky diode was estimated with and without the effect of series resistance. Surface states density was highly reduced after the elimination of the series resistance effect. Electrical parameters show an improvement of the electrical quality of the fabricated Au/GaN/GaAs Schottky diode.