Development on in-situ observation techniques for surface reaction process under hydrogen atmosphere related to alloy semiconductors

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In order to develop in-situ observation technique applicable to surface reaction process during crystal growth of alloy semiconductors under hydrogen atmosphere, sum frequency generation method (SFG) has been examined for observation of GaAs surfaces by contrast with conventional vacuum based method and reflectance anisotropy spectroscopy (RDS). The results obtained are as follows.Firstly, hydrogen and nitrogen adsorbed GaAs surfaces have been studied by RDS, and it is found that Ga and As dimer bond breaking has been took place during hydrogen exposure. Ga-rich surface is more reactive than As-rich surfaces for nitrogen, and development of new signal at 3.5eV has been observed during nitridation of Ga-rich surface.Secondly, observation system for surface SFG based on second harinonic light and infrared light obtained from Nd : YAG laser has been developed and methanol adsorbed GaAs surface has been studied. Resonance of symmetric vibration of methyl base has been observed in addition to that of bulk. Incident azimuth dependence of SFG intensity has been analyzed based on simple three states model, and direction of axis of methyl base has been determined. These results indicate that SFG method is to be a powerftul method on analyzing surface reaction process of alloy semiconductors.