In-situ monitoring and control of InGaP growth on GaAs in MOVPE

M. Zorn^a, T. Trepk^a, P. Kurpas^b, M. Weyers^b, J.-T. Zettler^a, W. Richter^a

^aTechnische Universität Berlin, Institut für Festkörperphysik, Hardenbergstr. 36, D-10623 Berlin, Germany
^bFerdinand-Braun-Institut für Höchstfrequenztechnik, Rudower Chaussee 5, D-12489 Berlin, Germany

Published in:
J. Cryst. Growth, vol. 195, no. 1-4, pp. 223-227 (1998).
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Abstract:
The growth of InGaP on GaAs was investigated and controlled by in situ reflectance anisotropy spectroscopy (RAS) and spectroscopic ellipsometry (SE). In contrast to other III-V semiconductors, the CuPt_B-type ordering of the group III sublattice in the InGaP material system causes a characteristic bulk anisotropic contribution to the optical constants. This contribution was determined by RAS between room and growth temperature. Based on this result the influence of the composition near the lattice matched composition on the optical data was studied by SE and used for closed-loop controlled growth of lattice matched InGaP on GaAs. For this purpose a photon energy of 3.5 eV was used where the contribution of the bulk ordering to the optical constants is negligible. Closed-loop controlled growth of lattice matched In_0.48Ga_0.52P on GaAs, i.e., the flux of the indium source was controlled directly by the ellipsometry computer, resulted in a lattice mismatch of 2x10^-4.

Keywords:
Reflectance anisotropy spectroscopy (RAS/RDS); Spectroscopic ellipsometry (SE); Metalorganic vapour phase epitaxy (MOVPE); In_xGa_1-xP; Ordering; Closed-loop-control

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