Investigation of Unexpected Residual Effects of Ultraviolet Based Measurements of SiO2/Si Interface by Photoluminescence

Unexpected residual effects of ultraviolet (UV) based measurements on SiO2/Si interface were studied using room temperature photoluminescence (RTPL) under various excitation wavelengths. Modulation (either increase or decrease) of RTPL intensity was measured from the UV exposed areas. Effects are investigated by controlled exposure with selected wavelength ranges and subsequent thermal treatments at 400°C and 800°C for 5 min in forming gas (96% N2 + 4% H2). Significant enhancement in RTPL intensity was observed and the residual effects were characterized after the thermal treatments. The mechanisms for RTPL intensity degradation after UV exposure and recovery after forming gas anneal are discussed.