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

The growth of InGaP on GaAs was investigated and controlled by in situ refl ectance anisotropy spectroscopy (RAS) and spectroscopic ellipsometry (SE). In contrast to other III-V semiconductors, the CuPtB-type ordering of the g roup III sublattice in the InGaP material system causes a characteristic bu lk anisotropic contribution to the optical constants. This contribution was determined by RAS between room and growth temperature. Based on this resul t the influence of the composition near the lattice matched composition on the optical data was studied by SE and used for closed-loop controlled grow th 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 co nstants is negligible. Closed-loop controlled growth of lattice matched In0 .48Ga0.52P on GaAs, i.e., the flux of the indium source was controlled dire ctly by the ellipsometry computer, resulted in a lattice mismatch of 2 x 10 (-4). (C) 1998 Elsevier Science B.V. All rights reserved.