Growth of CDTE on GaAs and Si Substrates by Organometallic Vapor Phase Epitaxy

Abstract

ABSTRACTEpitaxial (100) CdTe layers have been grown by organometallic vapor phase epitaxy (OMVPE) on GaAs and Si substrates. A thin layer of CdTe was first grown by atomic layer epitaxy (ALE) on GaAs substrates followed by thicker CdTe layer by conventional organometallic vapor phase epitaxy (OMVPE). This process resulted in high quality (100) CdTe on GaAs substrates. On Si substrates, direct growth of CdTe resulted in only polycrystalline layers. Hence, a thin Ge buffer layer grown at low temperature followed by an interfacial layer of ZnTe was used to get high quality (100) CdTe on Si. The process developed here eliminates the high temperature (>850°C) deoxidation step generally required when Si substrates are used. The CdTe layers were characterized by X-ray diffraction and optical microscopy. X-ray rocking curve with full width at half maximum (FWHM) of about 260 arcsec has been obtained for a 4 um thick CdTe layer. The results presented demonstrate novel techniques to control the hetero-interfaces in order to grow high quality CdTe on GaAs and Si substrates.