STUDY OF THE COMPOSITIONAL CONTROL OF THE ANTIMONIDE ALLOYS INGASB AND GAASSB GROWN BY METALORGANIC MOLECULAR-BEAM EPITAXY

MOMBE (metalorganic molecular beam epitaxy) growth characteristics of Sb containing ternary alloys, InGaSb, and GaAsSb are investigated. In the growth of InGaSb using TEGa (triethylgallium), TMIn (trimethylindium), and Sb4 (elemental antimony), the enhanced desorption of methyl-In molecules at a substrate temperature T(sub) of around 500-degrees-C as well as the enhanced desorption of ethyl-Ga molecules at around 515-degrees-C are observed. They are due to the weak bond strength of antimonide compounds. Furthermore, the decrease of Ga solid composition with increasing Sb4 flux and the increase of GaSb partial growth rate with TMIn flow rate are also observed at as high as 500-degrees-C. This is caused by the fact that the site blocking effect of excess Sb atoms exists up to higher T(sub). In the growth of GaAsSb using TEGa, TEAs (triethylarsine), and TESb (triethylstibine), the Sb composition versus TESb/(TEAs+TESb) curve exhibits a bowing characteristic, which is similar to that in the MOVPE (metalorganic vapor phase epitaxy) growth and is different from that in the MBE (molecular beam epitaxy) growth. Mass transport properties of Sb molecules in the MOMBE are considered to be similar to that in the MOVPE. It is found that the T(sub) dependence of Sb composition is much weaker than that in the MBE, which is a superior point of MOMBE in the growth of antimonide alloys.