Surface morphology of Si on Si(100) grown below 500°C using H/Cl exchange chemistry

Abstract

Changes in surface structure for thin epitaxial Si layers (Si*) grown on Si(100) below 500°C using alternating exposures to Si precursors are presented. Two different methods for growing Si* are compared, which involve a self-limiting exposure to Si2Cl6 followed by removal of the Cl layer with either Si2H6 or atomic hydrogen. Scattering and recoiling spectroscopy is used to depth profile a N marker layer as Si* is grown using Si2Cl6 and Si2H6 at TS=465°C. The decrease in the N marker intensity proves that a Si* film is grown, and reflection high-energy electron diffraction (RHEED) patterns show that the Si* is epitaxial. RHEED patterns from Si* grown using alternating exposures of Si2Cl6 and atomic hydrogen are nearly identical to clean Si(100), again indicating epitaxial growth. Both methods suppress formation of three-dimensional islands, which are observed for Si growth from Si 2H6 below TS=600°C.