Characterization of interface quality between various low-temperature oxides and Si using room-temperature-photoluminescence and Raman spectroscopy

The quality of interface between ultrathin silicon dioxide films and their silicon (Si) wafers was characterized using room-temperature photoluminescence (RTPL) and Raman spectroscopy. Three types of low-temperature (350 °C or room temperature) oxide films on Si grown by different techniques were measured and compared with Si wafers having native oxide and high-temperature thermally grown oxide films. Significant RTPL spectra and intensity variations were measured among low-temperature oxide films. Very strong excitation wave length dependence of RTPL spectra and intensity was observed from the low-temperature oxide films on Si whereas the RTPL spectra and intensity from Si with native oxide and thermally grown oxide films were consistent. Stress in the Si lattice, with different low-temperature oxide layers, showed noticeable differences depending on the oxidation technique used. Key device performance parameters of image sensor devices fabricated using three different low-temperature oxide films showed good correlation with the RTPL and Raman measurement results. The RTPL spectra and Raman shifts are very sensitive to the quality of the oxide/Si interface and can be used as an interface quality monitoring technique.