Molecular Beam Epitaxical Growth of Al x Ga 1-x As on Non - Planar Patterned GaAs (100)
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MOLECULAR BEAM EPITAXICAL GROWTH OF Alx Gal_×xAs ON NON-PLANAR PATTERNED GaAs(100) S. Guha, A. Madhukar, K. Kaviani, Li Chen, R. Kuchibhotla, R. Kapre, M. Hyugaji and Z. Xie
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In the list of authors, as "M. Hyugaji."
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The authors' address should read as "University Southern California, Los Angeles, CA 90089-0241."
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Acknowledgments at the end of the paper should read as: "This work was supported by the Air Force Office of Scientific Research, the Office of Naval Research, and the Army Research Office."
"M. Hyugachi" should be spelled of
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MOLECULAR BEAM EPITAXICAL GROWTH OF AlxGaa_xAs ON NON PLANAR PATTERNED GaAs (100) S. GUHA, A. MADHUKAR, K. KAVIANI, LI CHEN, R. KUCHIBHOTLA, R. KAPRE, M. 1tYUGACHI AND Z. XIE University of Southern California, Los Angeles, CA 90007 ABSTRACT We have examined some aspects of inter-facet migration during molecular beam epitaxical(MBE) growth of AlGatlxAs on patterned GaAs (100) substrates. Scanning and cross-sectional transmission electron microscopy are employed to examine the evolution of the growth front profile. We observe significant inter facet migration from (3111/1411) facets which originate from the terrace edges to the flat terrace region. The migration length of cations on these facets is at least 0.9 pim for GaAs growth while for AI0. 5Ga 0 . 5 As it is less than 0.3 pm. We also observe a decreasing inter- facet migration rate with increasing growth. This interfacet migration is exploited for in situ, growth kinetics controlled, creation of laterally confined quantum well structures on the top terrace region and photoluminescence results for these structures are presented. I. INTRODUCTION Since the early work of Tsang and Cho [1] on MBE growth on patterned GaAs substrates, work in this field has picked up primarily motivated by achieving lateral confinement of photons and electrons. Work has been done on GaAs/AlxGaltxAs laser structures utilising either lateral refractive index variations[2,3J or differences in band gaps of quantum wells on the base and sidewalls to induce lateral carrier confinement[4]. Some general observations regarding growth on patterned substrates include the observation of different growth rates on different facets, occurrence of new facets( e.g. (31 1), (411]), Several 18111 etc.) and compositional variations from facet to facet [1-61. parameters affect these properties. Notable among them are the specific growth conditions which in turn control the cation surface kinetics for compositional and structural variations, the role of the starting pattern size/shape, and the various preparation steps, including the free etching of the substrate prior to loading into the MBE chamber and the oxide desorption event. In this paper we present some results of a systematic study which examines the occurrence of new facets and the nature and extent of inter-facet migration for AixGal.xAs growth. II. EXPERIMENTAL GaAs (100) substrates were patterned via optical lithography and wet chemical etching in the form of parallel grooves aligned along [OTI
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