Low Surface Recombination Velocity on (100) Silicon by Electrochemically Grown Silicon Dioxide Annealed at Low Temperature

Abstract

This letter investigates silicon dioxide (SiO2) layers that are electrochemically grown in nitric acid (HNO3) at room temperature. It examines the dependence of surface recombination velocity (SRV), oxide charge, interface states, and oxide thickness on the concentration of HNO3. The results show that an SRV of less than 40 cm/s can be attained after SiO 2 is annealed at 400 °C in oxygen first and then forming gas. This SRV is similar to that attained by the best thermal oxides. Photoconductance and capacitancevoltage measurements indicate that the low SRV is caused by a large positive charge rather than a low interface state density. The SRV is found to degrade due to a decrease in charge and an increase in interface states, where the rate depends on the HNO3 concentration in which the SiO2 layer was grown.