Electron-Beam Exposure(EBE) and Epitaxy of GaAs Films on CaF2/Si Structures

Abstract

A novel heteroepitaxial method (electron-beam exposure and epitaxy: EBE-epitaxy) has been developed for growing GaAs films on top of CaF₂/Si(111) structures. In this method, the surface of CaF₂films is modified by an electron beam (e-beam) under arsenic impingement prior to the growth of GaAs films. It has been found that this EBE-epitaxy is very effective in improving the quality of the GaAs films such as surface morphology, crystallinity and crystallographic orientation. The principal effects in the EBE-epitaxy to improve the crystalline quality are considered based on these experimental results to derive a model of the growth mechanism. Other effects, such as electron energy dependence, substrate temperature dependence during e-beam exposure and GaAs growth temperature dependence, are also investigated systematically. Subsequently, the growth condition for an ideal EBE-epitaxy is discussed.