Atomic Image Observation and nano area Analysis of Epitaxial Process of Metals on Semiconductor by Ultrahigh Vacuum Scanning Electron Microscopy

点击翻译按钮获取中文摘要

In 1992, we constructed a small vacuum chamber in which we can check sample surface condition, and combined it to the ultrahigh vacuum scanning electron microscope(UHV-SEM). We completed a SEM apparatus in which we can study beforehand the surface structures by reflection high energy electron diffraction(RHEED) and surface elementaly analysis by total reflection angle X-ray spectroscopy(TRAXS) and then the sample can move into SEM apparatus without exposing it in air.We deposited Au, Ag, Bi, Ga, In etc.on a Si(111) surface and investigated the surface structures and surface compositions. These surfaces were also observed by UHV-SEM.When 1ML(mono layr) of Bi was deposited on the Si(111)-7X7 surface, three types of contrast, B(beta-ROO<3>XROO<3>), M(alpha-ROO<3>XROO<3>) and D(7X7) were observed. The contrast B and M were clerly observed along the substrate steps and anti-phase domain boundaries of th 7X7 structure.In 1993, we studied the composition analysis of nano meter area by TRAXS in UHV-SEM.The investigated surfaces were In/Si(111)-7X7, In/Si(111)-4X1-In, In/(Si(111)-ROO<3>XROO<3>-Ga, Ga/Si(111)-7X7, Ga/Si(111)-ROO<3>XROO<3>-Ag, Ag/Si(111)-ROO<3>XROO<3>-Ga etc.(In_2Ga)In structure which was formed when 3ML of In were deposited on the Si(111)-ROO<3>XROO<3>-Ga showed specially intresting SEM images. This structure showed a very flat structure within a terrace. For futher deposition In layr incresed layr by layr fasion without the steps within a terras, resulting in an interesting structure which shuld be denoted (In_2Ga)In_m(m=1,2,3...). Thus, we obtained many interesting results in this study.