We demonstrated the high quality growth of exceedingly thick pseudomorphic layers on free-standing, compliant substrates using InGaAs and GaAs materials. A 1% compressively strained InGaAs layer was grown on a relaxed GaAs platform by MBE. We fabricated the 800 Å-thick compliant platforms before growing a lattice-mismatched layer that exceeds its critical thickness by about twenty times.
X-ray analysis confirms a shift in the InGaAs peaks grown on the compliant substrate. Such shifts are characteristic of strained layers. Atomic Force Microscope analysis verifies that the layers on compliant substrates are much smoother than layers grown on a plain substrate.
Pseudomorphic growth exceeding the critical thickness has important applications in the design of various electronic and photonic devices.