THE MORPHOLOGY OF CDTE DEPOSITED BY ORGANOMETALLIC VAPOR-PHASE EPITAXY - THE EFFECT OF SUBSTRATE MISORIENTATION

Substrate misorientation and growth temperature influence the morpholo gy of CdTe epilayers grown by organometallic vapor phase homoepitaxy. These effects were investigated by using CdTe{100} and CdTe{100} misor iented by 2, 4, 6, and 8 degrees toward <111>(Te) as substrates for gr owth in the temperature range from 337 to 425 degrees C. Low angle pyr amidal facets appeared on films grown on the CdTe(100) surface. The nu mber density of these pyramidal facets decreased to zero as the substr ate misorientation angle increased to 4 degrees. At higher misorientat ion angles, low angle protrusions, resembling fish scales, appeared on the surface. When the temperature was increased, facet size decreased but facet density increased. The film morphology at the high misorien tations, however, improved remarkably with increasing temperature. Cro ss-sectional transmission electron microscopy provided evidence that b oth the faceted CdTe films and films with a mirror-like finish were ep itaxial single crystals with no planar defects. Schwoebel barriers are suggested as the reason for the faceting of the surface grown on CdTe {100}.