Heteroepitaxy of CdTe on {211} Si using crystallized amorphous ZnTe templates

Abstract

CdTe films were grown by molecular-beam epitaxy on As-passivated nominal {211} Si substrates using thin interfacial ZnTe buffer layers. ZnTe layers were grown by the following two growth methods: (1) migration enhanced epitaxy (MEE) directly on Si and (2) MEE on 80 Å templates of crystallized amorphous ZnTe buffers deposited directly on Si. CdTe films thicker than 8 μm had threading dislocation densities in the range of 2.5 to 4×106 cm−2 and 1 to 2×106 cm−2 for methods (1) and (2), respectively. Double crystal x-ray rocking curve peak widths decreased from 550 to 120 arcsec as CdTe film thickness increased from 3 μm to 9 μm for samples grown by method (1), and for samples grown by method (2), peak widths decreased from 300 to 84 arcsec in the same thickness range. CdTe film grown on vicinal {211} Si substrates misoriented by 5° toward [111] with ZnTe buffer layer prepared by method (2) had a dislocation density of 8×105 cm−2 and an x-ray peak width of 72 arcsec.