Experimental test for elastic compliance during growth on glass-bonded compliant substrates

Highly mismatched films (In0.44Ga0.56As, 3% mismatch) grown well beyond the ir critical thickness (to 3 mu m) on GaAs glass-bonded compliant substrates exhibit surfaces four times smoother and strain distributions twice as nar row as films grown simultaneously on conventional GaAs substrates. The comp liant substrates consist of a thin (similar to 10 nm) GaAs template layer b onded via a borosilicate glass to a mechanical handle wafer. The improvemen t of highly mismatched films grown well beyond their critical thickness on compliant substrate structures is commonly modeled in terms of an elastic p artitioning of strain from the film to the thin (similar to 10 nm) single-c rystal template layer. The present study is a direct test for this mechanis m of elastic compliance. A comparison is reported of the strain in 92 nm In 0.09Ga0.91As films and 76 nm In0.03Ga0.97As films grown simultaneously on c onventional GaAs substrates and the compliant substrates responsible for th e improved structural quality of In0.44Ga0.56As films. Elastic partitioning of strain from the mismatched film to the 10 nm template layer prior to th e onset of misfit dislocations is not observed for films grown on these gla ss-bonded compliant substrates. (C) 2000 American Institute of Physics. [S0 003-6951(00)03318-0].