A thin twin-free layer was successfully formed on the top of InGaAs micro-discs via multi-step growth using micro-channel selective-area MOVPE on Si(111) substrates. The multi-step growth employed a gas flow sequence in which the partial pressure of the Ga source (trimethylgallium) was modulated to control the initial nucleation and the direction of subsequent growth. The in-plane uniformity of the crystal shape of InGaAs micro-discs had previously been improved by 3-step growth that started with InAs nucleation. Using these micro-discs as templates, InGaAs with tripled partial pressure of trimethylgallium was grown as the fourth step. The growth of this fourth layer on the disc surface seemed to suppress the layer-by-layer growth on the (111) plane and to terminate rotational twins, as well as keeping the size deviation of micro-discs under 25%. One of the most laterally grown micro-discs (with thickness of 380nm and width of 7.1μm) had a 50nm-thick twin-free layer on the top.

Twin-Free InGaAs Thin Layer on Si by Multi-Step Growth using Micro-Channel Selective-Area MOVPE. M.Deura, Y.Kondo, M.Takenaka, S.Takagi, Y.Nakano, M.Sugiyama: Journal of Crystal Growth, 2010, 312[8], 1353-8