Investigation of organometallic vapor phase epitaxy of InAs and InAsBi at temperatures as low as 275 °C

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Abstract
InAs and InAsBi have been grown by atmospheric pressure organometallic vapor phase epitaxy (OMVPE) over a broad temperature range from 600 to as low as 275 °C. This is the lowest growth temperature ever reported for standard OMVPE. It is demonstrated that lowering the growth temperature is the most effective approach for increasing the Bi content in InAsBi alloys. For example, InAsBi samples with Bi concentrations as high as 6.1 at.% have been successfully grown at a temperature of 275 °C. Trimethylindium, arsine, and trimethylbismuth were used as precursors for most experiments. The growth efficiency is a constant for temperatures above 400 °C, indicating the growth rate is diffusion limited in this temperature regime. For lower temperatures, it decreases exponentially with decreasing temperature with an activation energy of 24 kcal/mol. Incomplete pyrolysis of TMIn limits the growth rate in this temperature regime. However, by substituting ethyldimethylindium for TMIn the diffusion controlled regime can be extended to lower temperatures. Hall effect measurements show that the n‐type background concentration increases from approximately 2.3×1016 to 1019 cm−3 as the growth temperature decreases from 600 to 325 °C. Secondary‐ion mass spectroscopy results show that the dominant impurity is carbon. Thus, carbon is mainly a donor in these materials.