Selective epitaxy of GaAs, AlxGa1−xAs, and InxGa1−xAs

Epitaxial growth of a nanoscale, vertically faceted, one-dimensional, high-aspect ratio grating in III-V materials for integrated photonics

“…2,3 Several papers on patterned GaAs growth have been reported, but ͕110͖-type sidewall facets vertical to a ͑001͒ substrate have not previously been achieved. [4][5][6][7][8][9] Depending on the growth rate, the thickness and profile of the masking material employed for selective epitaxy, and the direction of the patterns, the resulting facets at a substrate-mask boundary can be vertical. We demonstrate the formation of ͕110͖ facets exactly vertical to a ͑001͒ substrate surface and with very low surface roughness by directed self-assembly, and interpret the kinetics of faceting in patterned growth as resulting from minimization of the total surface energy.…”

“…There have been several reports on selective epitaxy on a patterned substrate. [4][5][6][7][8][9] Most of these works have been done by metal-organic vapor phase epitaxy ͑MOVPE͒. It has been reported that growth on a stripe opening directed to ͓110͔ is terminated with forming an isoscales triangular cross section which consists of ͑111͒B sidewalls, 5 or laterally proceeds over a mask with the evolution into a polygonal cross section without ͑110͒-type facets as a major sidewall.…”

“…It has been reported that growth on a stripe opening directed to ͓110͔ is terminated with forming an isoscales triangular cross section which consists of ͑111͒B sidewalls, 5 or laterally proceeds over a mask with the evolution into a polygonal cross section without ͑110͒-type facets as a major sidewall. 6,7 One of the possible reasons for the absence of vertical faceting in MOVPE is deposition rate, which affects surface migration and diffusion. In MOVPE, we observe the vertical faceting similar to that presented in this work when the deposition rate is reduced to ϳ0.2 ML/ sec.…”

Competitive Adsorption as a Route to Area-Selective Deposition

“…Self-aligned ASD processes, in particular, also require that the deposition process exhibits a dependence on substrate composition, involving a growth and nongrowth surface. Successful ASD processes have been demonstrated for some time using chemical vapor deposition (CVD), − and more recently using atomic layer deposition (ALD). − For each deposition technique, there are several successful examples representing different material systems, as well as different approaches to achieve selectivity. One distinguishing factor concerning growth via CVD vs ALD is that the former is often conducted at relatively high temperatures where the reversibility of adsorption can be exploited.…”