Demonstration of a GaAs-based compliant substrate using wafer bonding and substrate removal techniques

A GaAs-based compliant substrate that uses an intermediate AlGaAs-oxide layer to separate thin 150 Å-1000 A GaAs compliant layers from a GaAs host substrate is described. The compliant substrates and epitaxial layers of lattice-mismatched In_0.15Ga_0.85 As were studied using atomic force microscopy and double-crystal X-ray diffraction. The surface morphology of the 1000 A compliant substrate prior to growth had an RMS and peak-to-peak roughness of 10 Å and 100 Å. Following growth of 3000 Å In_0.15 Ga_0.85 the root mean square (RMS) roughness increased to 50 Å, and slip lines were observed in the (110) direction. A comparison of lattice-matched p⁺-n junction diodes grown on a substrate with a 1000 Å compliant layer and a standard GaAs substrate revealed similar dark current-voltage characteristics, which demonstrate the high quality of the compliant substrate