Study of CdTe epitaxial growth on (211)B GaAs by molecular-beam epitaxy

Abstract

Recently, misoriented (100)GaAs or (211)GaAs substrates have been found to be favored for HgCdTe and CdTe epitaxial growths, due to low occurrence of crystalline defects. It was previously reported that both tilted (211) and (133)CdTe were grown on (211)B GaAs, like on (100)GaAs, and that (133)CdTe seemed to have better crystallinity than tilted (211)CdTe. However, these results were obtained only at substrate temperature ∼300 °C, and the occurrence of both growth orientations has not been clear yet. In this article, substrate temperature dependence of CdTe growth on (211)B GaAs substrate is studied in detail, from the view points of crystallinity and surface morphology. It turns out that these orientations can be controlled by the initial substrate temperature, i.e., tilted (211)CdTe appears at substrate temperature below 290 °C, and above 290 °C (133)CdTe can be grown. Furthermore, double-crystal rocking curve-full width at half-maximum reaches 60 arcsec for (133)CdTe/(211)B GaAs. Finally, a model for the occurrence of both tilted (211) and (133) CdTe growths was qualitatively proposed.