Effect of thermal oxidation on Si/SiO2 interface microroughness:: An atomic force microscopy (AFM) study

Three groups of samples under different preparations are used to illustrate the effect sf thermal oxidation on Si/SiO2 interface roughness Two groups are roughened intentionally, and the other one is only treated with a regular pre-oxidation clean. In general, interface roughness is a strong function of oxide thickness. For samples of two intentionally roughened groups, interface roughness always decreases as oxide thickness increases, In contrast, samples only treated by a regular pre-oxidation dean demonstrate a different quantitative trend: Si/SiO2 interface is initially roughened and there becomes smooth as oxide thick-ness increases. This implies that the evolution of interface roughness is dependent on the sample preparation or the starting surface. Our results also suggest that oxidation ambient does not have a significant influence on Si/SiO2 interface roughness.