GROWTH OF (100) ORIENTED CDTE ON SI USING GE AS A BUFFER LAYER

Epitaxial (100) CdTe layers have been grown on (100) oriented Si substrates by atmospheric pressure organometallic vapor phase epitaxy using thin Ge as a buffer layer. A very thin native oxide layer may be present on Si substrates after etching in a HF solution and this can be removed by passing GeH4 gas over Si at 450 degrees C. The removal of this oxide takes several minutes depending on the pride layer thickness and reactor conditions. For the CdTe layers grown on Ge/Si substrates, single-crystal (100) CdTe can be obtained at growth temperatures higher than 420 degrees C. For growth temperatures below 420 degrees C, a mixture of both (100) and (111) oriented CdTe was present. The x-ray full width at half-maximum of the (400) peak was 780 arcsec for a 3.1-mu m-thick CdTe layer grown at 450 degrees C with a Ge buffer. Although all the layers had antiphase domains, single-domain CdTe can be grown on (100)Si misoriented towards [110]. This result presents an alternative for nucleating CdTe on Si without a GaAs buffer layer.