MOMBE (METALORGANIC MOLECULAR-BEAM EPITAXY) GROWTH OF INGAALASSB SYSTEM ON GASB

MOMBE (metalorganic molecular beam epitaxy) growth characteristics of materials in the InGaAlAsSb system on GaSb substrates are described. The studies on GaSb growth using TEGa (triethylgallium) and solid Sb sources show that the surface reconstructions and the excess Sb on the surface play important roles in the MOMBE growth process. This is explained by a model which includes group V chemistry. The use of TESb (triethylstibine) instead of solid Sb indicates that the alkyl species coming from thermally cracked TESb also play important roles. Crystalline AlSb films are obtained using TIBAl (triisobutylaluminium), while not when using TMAl (trimethylaluminium), which is related to the difference in the reaction process. In the growth of InAsSb using TMIn (trimethylindium), TEAs (triethylarsine) and TESb, mirror-like surfaces are obtained only in the narrow TEAs/TMIn flux ratio region close to the (2x4)-(4x2) surface reconstruction transition boundary in InAs growth, and it is found that the composition of InAsSb alloy films can be controlled precisely using TMIn, TEAs and TESb. The growth characteristics of InAs and InSb are also discussed. Finally, preliminary results on the electrical and optical properties of the layers are shown to be encouraging.