Space-charge generation properties of gold in MOS structures

Abstract

The generation lifetime, capture cross section, and thermal emission rates for the gold acceptor level in bulk silicon have been studied using MOS techniques. The experimental methods used were the pulsed high-frequency capacitance-time and nonequilibrium linear-voltage-ramp techiniques at various temperatures. By correlating the results of the above measurements, the capture cross section σ and trap energy Et of the gold acceptor state were determined as a function of temperature in the range 235–265 °K. It was observed that σ increases with increasing temperature and has a value of the order of 1.0×10−15 cm2. On the other hand, the trap energy Et was found to decrease with increasing temperature, suggesting that it varies in unison with the silicon energy gap. Finally, from the above results the thermal emission rates en and ep were determined, with the assumption that the degeneracy factor and gA=1. For the temperature range investigated, the ratio en/ep varied from 30 at 235 °K to 20 at 265 °K.