Si(113)表面原子结构的低能电子衍射研究

A LEED STUDY OF ATOMIC STRUCTURE ON Si(113) SURFACE

利用低能电子衍射(LEED)研究了离子轰击加退火处理的和淀积外延的两种Si(113)表面的原子结构。发现对于经750—800℃退火后的两种Si(113)表面,当其温度高于600℃时存在1×1非再构表面相。随着样品温度缓慢地冷却至室温,Si(113)-1×1表面经过3×1(约600—400℃)最后转变为3×2再构。当退火温度为600℃时,则只出现3×1再构,室温下的3×2和3×1表面都是很稳定的。讨论了表面杂质对Si(113)表面原子结构的影响。在衬底温度为580℃的Si(113)表面上进行淀积生长,当外延层厚度约为20个原子单层时,未经退火处理的表面仍显示为清晰的3×1结构。从而证明,利用Si(113)作为衬底进行外延,可获得很完整的表面。

By using low energy electron diffraction (LEED), the atomic structures on Si (113) surfaces were studied. These surfaces were prepared by both ion bombardment followed by annealing (IBA) and epitaxial growth. When tbeannealing temperature was higher than 750℃, a 1 × 1 unreconstructed structure was observed above 600℃ for both kinds of surfaces. Cooling the specimen from the annealing temperature at a rate of 5℃/min, we found that the surface structure converted from the 1×1 through 3×1 (beteen 600℃ and 400℃) to the final 3×2 superstructure. A lower annealing temperature (~600℃) results in a 3×1 superstructure only. Both 3×2 and 3×1 structures are very stable at room temperature. The influence of surface impurities on the Si(113) surface structure was discussed. The clear 3×1 superstructure was also appeared on the initial Si(113) surface of about 20 monolayers thick epitaxial film grown by evaporation method.