Investigation of Light Initiated Oxidation of Hydrogen Passivated Silicon Surfaces: Hx-Si(100) and H-Si(111)(1X1)

Abstract

AbstractThere are factors present in cleanroom air that may lead to contamination prior to processing. These factors need to be better understood in order to meet tomorrow's requirement for atomically clean surfaces prior to gate oxidation. This paper identifies the conditions that initiate room temperature oxidation of fluoride prepared hydrogen passivated silicon surfaces by using X-ray Photoelectron Spectroscopy (XPS). Possible oxidation factors investigated include lighting conditions and ambient gases. Both Hx-Si(100) and H-Si(111)(1X1) surfaces do not oxidize in dark conditions and in 450nm wavelength lighting conditions for both humid and dry air ambients. These surfaces do oxidize in dry air and humid air when the surface is exposed to shorter wavelengths of light. Wavelength dependence for oxidation on both surfaces is confirmed. In addition, the level of oxidation observed depends on the surface orientation in humid air but not in dry air.