Growth of Si Thin Films on CeO2/Si(111) Substrate Using Electron-Beam Evaporation

Abstract

The growth mechanism of Si film on a CeO2(111)/Si(111) substrate has been investigated using X-ray diffraction (XRD), double crystal XRD (DCXRD), transmission electron microscopy (TEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). We have epitaxially grown a CeO2 film on the Si(111) surface by deposition of CeO2 at 640°C. When Si was deposited at 620°C on the CeO2(111)/Si(111) substrate using a high-vacuum e-beam evaporator, it was observed from XRD analysis that the Si film grew along the [111] direction. The TEM and AFM images showed that the top Si layer consists of large mountains and deep valleys. The XPS data showed no segregation of Ce on the Si layer surface. However, there was slight diffusion of Ce along the top layer Si grain boundary. These analysis results reveal that at the early stage of deposition, Si crystal nuclei are formed on a domain of the CeO2 film on Si(111) and grow three-dimensionally along the [111] direction, and eventually these merge into large mountains.