Study of oxide-silicon interface state generation and annihilation by rapid thermal processing

Abstract

To investigate the mechanism of interface state generation and annihilation by rapid thermal processing (RTP), the interface state density Dit and the mechanical stress between silicon and oxide layers were measured using a surface charge analyzer and the curvature of the wafers, respectively. After RTP, Dit increases up to 750 °C and then decreases above 800 °C. The stress in the oxidized wafer increases linearly with temperature up to 700 °C; however, above this temperature, it saturates owing to the viscosity of the oxide. From the RTP temperature dependence of the relaxation time of the interface state annihilation, the activation energy is obtained as 1.36 eV. The same value is estimated assuming the Arrhenius-type relaxation process from the reported viscosity data. The decrement in Dit by RTP at high temperatures is attributed to the viscous flow in the oxide layer.