We have studied the initial stages of oxidation of the hydrogen-terminated Si(111) and (100) surfaces stored in air, using infrared spectroscopy in the multiple internal reflection geometry. We investigate the effect of surface roughness and humidity of air on the oxidation of the hydrogen-terminated Si surfaces. We suggest that surface roughness on a microscopic scale does not significantly affect the oxidation of the hydrogen-terminated Si surface and the oxidation occurs on the entire surface. It is demonstrated that water is predominantly involved in the oxidation of the surface Si—H bond, and that the surface Si—H bond is quite inert to the oxygen molecule.

We have investigated the initial stages of UV ozone oxidation of hydrogen-terminated Si(100) and (111) surfaces using infrared spectroscopy in the multiple internal reflection geometry. Spectral features due to intermediate oxidation species such as SiH2(O2) and SiH(O3), which are generated by the attack of the back bonds of a surface Si atom by oxygen, are clearly observed. Upon UV ozone oxidation the concentration of the intermediate oxidation species initially increases and then drops, while that of surface hydride species Si–Hx decreases with increasing the UV ozone exposure, which indicates that at initial stages of oxidation oxygen attacks both of the Si–H and back bonds of a Si atom in the outermost layer. We find that the generation of the intermediate oxidation species exhibits a strong crystallographic orientation dependence; both SiH2(O2) and SiH(O3) are generated on the Si(100) surface, while the generation of the SiH2(O2) species is suppressed on the Si(111) surface.

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We have previously proposed a method for depositing silicon dioxide films on Si from tetraethoxysilane Si(OC2H~)4 (TEOS) using ultraviolet (UV) light from a low pressure mercury lamp. In the method, an organic solution which contains TEOS is spin-coated onto a Si wafer surface to form a thin organic film which is then exposed to the UV light to synthesize silicon dioxide. The photochemical reactions responsible for the oxide formation and the thermal properties of deposited films have been investigated using infrared (IR) and UV absorption spectroscopy and thermal desorption spectroscopy (TDS). IR and UV absorption data confirm that the UV light decomposes organic compounds in the spin-coated organic film to conve~'t the film into a silicon dioxide film. We show that some photochemical reactions responsible for the decomposition of organic compounds are two-step processes. TDS data demonstrate that the deposited film is stable from substrate heating to approximately 400~

Selective area, synchrotron radiation induced, delta doping of silicon J. Appl. Phys. 71, 4795 (1992); 10.1063/1.350619 Degradation of hydrogenated amorphous silicon films induced by irradiation of synchrotron radiation lightThe authors have investigated the synchrotron radiation ͑SR͒ induced chemical reactions of condensed layers of silicon alkoxides, tetramethoxysilane Si͑OCH 3 ͒ 4 and tetraethoxysilane Si͑OC 2 H 5 ͒ 4 , adsorbed on a Si substrate at 80 K. Photon stimulated desorption measurements show that irradiation with SR in the vacuum-ultraviolet region induces the desorption of hydrogen, hydrocarbon, and carbon monoxide from the condensed layer, indicating that the radiation decomposes the alkoxyl group in the silicon alkoxides. Infrared absorption and photoemission data demonstrate that Si-containing fragments produced by the decomposition of silicon alkoxide molecules are polymerized to form silicon oxide. The experimental results show the possibility of deposition silicon oxide film from silicon alkoxides using intense SR in the VUV region.