Substrate orientation and surface morphology improvements for InSb grown by metalorganic chemical vapor deposition

Abstract

Misoriented InSb substrates were used for the growth of InSb with two new organometallic Sb sources, tris(dimethylamino)antimony (TDMASb), and tertiarybutyldimethylantimony (TBDMSb). The surface morphology of InSb grown using either TDMASb or TBDMSb was very rough for growth temperatures ≤ 425°C. This surface roughness is associated with low temperature and excess Sb or high V/III ratios. Smoother surfaces were generally found when using off-axis substrates. The details of the defects observed on the surfaces were dependent on the type of misorientation and can be related to the atomic structure of the surface steps. The smoothest surfaces were obtained for growth on InSb substrates misoriented 5° towards the <111>;In planes. Both n-and p-type InSb were grown using TBDMSb or TDMASb and TMIn with mobilities up to 68,990 and 7773 cm 2/V · s, respectively, at 77 K. The mobility for InSb using either TDMASb or TBDMSb was improved by going to lower temperatures (400°C), pressures (215 Torr) and V/III ratios (2–4). The surface morphology improved with higher temperature (475°C), and lower pressure (215 Torr), with little or no correlation to the V/III ratio. The growth of high mobility InSb with smooth surfaces at temperatures ≤ 425°C was not achieved with TDMASb or TBDMSb and TMIn under the conditions investigated in this work.