Development of a glass-bonded compliant substrate

The critical thickness limitation for lattice-mismatched heteroepitaxial growth could potentially be removed by the use of a compliant substrate. This work presents initial results for the development of a compliant substrate consisting of a similar to 10 nm GaAs layer (template layer) bonded to a GaAs "handle wafer" through a borosilicate-glass. The glass concentration is chosen to have a moderate viscosity at the temperature used during lattice-mismatched growth. Compliant substrates using 30 and 50 mol% B2O3 glass as the bonding layer were used in the growth of 2 mu m of In0.40Ga0.60As (similar to 3.1% lattice mismatch to GaAs). X-ray diffraction demonstrated that epitaxy was achieved between the growth and template layer. Optical microscopy, atomic force microscopy, and scanning electron microscopy were also used to characterize both the initial borosilicate-glass-bonded compliant substrate as well as the grown structures. (C) 1998 Elsevier Science B.V. All rights reserved.