Studies of Surface Reaction on Solids by Using Suprathenal Beams.

点击翻译按钮获取中文摘要

(1) We studied the growth mechanism of beta-Sic film formation on Si (001) surface by reaction of Si with C_2H_2 molecular beams. The film was formed above the surface temperature of 1000K. Under the condition that the surface reaction was limited by the small beam flux, the film grew epitaxially. But, under the condition that the beam flux was too large for the reactive Si atoms on the surface, the film growth rate decreased due to formation of the carbon rich layer on the surface, and many hillocks were observed in the grown film.(2) Desorption kinetics of SiO in the reaction of O_2 with Si (100) and (111) surfaces were investigated at surface temperatures between 1000 and 1300K by using a pulsed molecular beam technique. At lower temperatures than 1050K, the SiO signal appeared with an induction time after the O_2 beam irradiation onto the surface, which means that desorption occurs via sequential steps. The rate constants for two steps were obtained by a computer simulation of the … More relaxation waveforms of the SiO signal.(3) In order to study the interaction between the solid surface irradiated by ultra violet laser and the colliding molecules, we detected the outcoming molecules from the surface after the laser irradiation by a mass spectrometer and determined their kinetic energies by a time-of-flight method. We noticed that the energetic molecules having a few eV were produced in the process. The mechanism is now under the investigation.(4) Water-absorbed Si (100) surface were bombarded by a pulsed low energy (500) Ne^+ beam. Time-of-flight spectra for neutrals plus positive ions or neutrals only were measured for the surface with various water coverages. By comparing the two kinds of spectra, the dependence of positive ion fractions of scattered Ne and recoiled O atoms upon water adsorption was studied. It was found that the Ne^+ and O^+ fraction changes in an opposite way depending on the water coverage such that the Ne^+ fraction decreases with increasing the coverage, whereas the O^+ fraction increases with it. Less