Current transport mechanisms and deep level transient spectroscopy of Au/n-Si Schottky barrier diodes

Abstract

The temperature-dependent electrical characteristics of the Au/n-Si Schottky diodes have been studied in the temperature range of 40–300 K. Current density–voltage ( J– V) characteristics of these diodes have been analyzed on the basis of thermionic emission theory with Gaussian distribution model of barrier height. The basic diode parameters such as rectification ratio, ideality factor and barrier height were extracted. Under a reverse bias, the conduction process at low voltage is determined by Schottky emission over a potential barrier but at higher voltage the Poole Frenkel effect is observed. The capacitance–voltage ( C– V) features of the Au/n-Si Schottky diodes were characterized in the high frequency of 1 MHz. The barrier heights values obtained from the J– V and C– V characteristics have been compared. It has been seen that the barrier height value obtained from the C– V measurements is higher than that obtained from the J– V measurements at various temperatures. Possible explanations for this discrepancy are presented. Deep level transient spectroscopy (DLTS) has been used to investigate deep levels in Au/n-Si. Three electron trap centers, having different emission rates and activation energies, have been observed. It is argued that the origin of these defects is of intrinsic nature. A correlation between C– V and DLTS measurements is investigated.