The hydrophilization of process wafers in dilute hydrogen peroxide solutions and ozonated deionized water and its effects on defects and gate oxide integrity

Abstract

The purpose of this study is to explore the effect of hydrophilization of wafer surfaces on defects and gate oxide integrity in metal-oxide semiconductor (MOS) devices. After HF treatment, dilute H2O2 solutions and ozonated deionized (DI) water were used as the final cleaning chemical to hydrophilize wafer surfaces. The defects created on patterned hydrophilic wafers were the least compared with patterned hydrophobic wafers or wafers with a mixture of both surfaces. The defects created on spin dried patterned hydrophobic wafers were water marks. The concentrations of Al, Ca and K observed in dilute H2O2 solutions and ozonated DI water were slightly higher than in DI water. Minority carrier lifetime values were the highest in HF last treated wafers and the lowest in those treated in dilute H2O2 solutions. MOS capacitors were fabricated to evaluate the gate oxide integrity when different cleaning procedures were applied. The distribution of breakdown range of devices shifted to a higher region on the application of HF and ozonated DI water. Dilute H2O2 solutions resulted in a poor breakdown held distribution. Ozonated DI water treated wafers showed higher breakdown field distributions than HF-last.