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Open Access item A growth method to obtain flat and relaxed In0.2Ga0.8As on GaAs (0 0 1) developed through in situ monitoring of surface topography and stress evolution

Authors:González, María Ujué
González, Yolanda
González, Luisa
Calleja, Montserrat
Silveira, Juan Pedro
García, Jorge M.
Briones Fernández-Pola, Fernando
Issue Date:Jul-2001
Citation:Journal of Crystal Growth 227-228: 36-40 (2001)
Abstract:In this paper we develop a growth process for obtaining flat and relaxed In0.2Ga0.8As layers on GaAs (0 0 1). The process designed is based on the results obtained by in situ and real time characterization of surface morphology and layer relaxation. In particular, our results show that for growth temperatures Ts200°C the relaxation of In0.2Ga0.8As layers is inhibited and the morphology does not evolve to a crosshatched pattern. After growth thermal treatments of these low-temperature (LT) In0.2Ga0.8As layers induce the development of a very faint (rms=0.5 nm) crosshatched-like morphology. The relaxation process during the thermal annealing is strongly asymmetric and the layers present a high final strain state. By growing on top of the LT layer another In0.2Ga0.8As layer at higher temperature, relaxation is increased up to R≈70% and becomes symmetric. Depending on the growth process of the top layers morphology evolution differs, resulting in better morphologies for top layers grown by atomic layer molecular beam epitaxy (ALMBE) at Ts=400°C. We have obtained 400 nm In0.2Ga0.8As layers with a final degree of relaxation R=70% and very flat surfaces (rms=0.9 nm).
Description:13 páginas, 3 figuras.-- PACS: 81.15.Hi, 81.05.Ea, 78.35.+c, 68.35.Bs.-- Comunicación oral presentada en el XI Molecular Beam Epitaxy (MBE-XI), Pekín (11/09/2000).
Publisher version (URL):http://dx.doi.org/10.1016/S0022-0248(01)00628-5
Appears in Collections:(IMM-CNM) Artículos

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