STRAIN ACCOMMODATION IN MISMATCHED LAYERS BY MOLECULAR-BEAM EPITAXY -INTRODUCTION OF A NEW COMPLIANT SUBSTRATE TECHNOLOGY

Compliant substrates allow a new approach to the growth of strained ep itaxial layers, in which part of the strain is accommodated in the sub strate. In this article, compliant substrates are discussed and a new compliant substrate technology based on bonded thin film substrates is introduced. This technology has several advantages over previously pu blished methods, including the ability to pattern both the top and bot tom of the material. A new concept enabled by this compliant substrate technology, strain-modulated epitaxy, will be introduced. Using this technique, the properties of the semiconductor material can be control led laterally across a substrate. Results of two experiments are prese nted in which low composition InxGa1-xAs was grown by molecular beam e pitaxy on GaAs compliant substrates at thicknesses both greater than a nd less than the conventional critical thickness. It was found that fo r t > t(c), there was an inhibition of defect production in the epitax ial films grown on the compliant substrates as compared to those grown on conventional reference substrates. For t < t(c), photoluminescence and x-ray diffraction show the compliant substrates to be of excellen t quality and uniformity as compared to conventional substrates.