Low pressure MOCVD growth of GaSb using trisdimethylaminoantimony (TDMASb)

The growth of nominally un-doped GaSb layers on GaAs substrates by low pressure MOCVD was investigated. The MOCVD reactor is a vertical type operating at growth pressure of about 50 torr. A flow guide was used to guide gas flow inside the reactor in order to obtain uniform layers. Trimethylgallium (TMGa) and trisdimethylaminoantimony (TDNUSb) were used as precursors. Growth temperatures were in the range of 475 - 580degreesC, while the V/III ratio was varied between 0.4 - 2.0. The effect of growth temperature and V/III ratio on the growth rate, crystallographic quality, surface morphology and electronic properties were investigated. It was found that the optimum growth conditions occur at very narrow growth temperatures, in the range of 530 - 540degreesC with V/III ratios of around 1.0. The growth rate significantly depends on the growth temperature. The grown layer was p-type and dominated by (200) and (400) X-ray diffraction reflections with the highest mobility of 616 cm(2)V(-1)s(-1) at hole concentration of 4.3 x 10(17) cm(-3).