Effect of Ar+ ion bombardment on the electrical characteristics of Al/n-Si contacts

Ion bombardment of aluminum contacts on n-type silicon has been investigated by measuring the I-V characteristics before and after implantation of Ar+. These characteristics have been quantified in terms of the saturation current, the ideality factor, and the diode series resistance. Before implantation, large variations in these parameters were found. After implantation, much more uniform characteristics were obtained but they were still far from ideality. Auger electron spectroscopy showed that very little mixing took place, but that the concentration of oxygen at the interface decreased. From α-particle channeling analysis it was ascertained that the implantation caused severe damage to the silicon. This damage was probably responsible for the observed increase in the series resistance.