Effect of hydrogen chloride during oxidation of silicon on trap generation by avalanche electron injection

Abstract

The effects of HCl on trap generation in silicon dioxide layers at high electric fields are reported by comparing 700-Å, 200-Å, 9% HCl, and 0% HCl dry oxides stressed at constant avalanche electron injection currents and voltages. Experimental data indicate that HCl decreases the hydrogenation rate of boron acceptor in the silicon surface layer due to a high-density chlorine layer at the oxide/silicon interface but HCl increases the density of the peaked interface trap at 0.3 eV above the silicon midgap. A new chlorine-related positively charged electron trap in the oxide is observed and isolated from the chlorine-independent negatively charged oxide hole trap. Chlorine also reduces the density of the smaller cross-section oxide electron trap which gives the turn-around phenomena.