CHARACTERIZATION AND MODELING OF THE STRAIN FIELDS ASSOCIATED WITH INGAAS LAYERS ON V-GROOVED INP SUBSTRATES

A series of lattice-matched or compressively strained InGaAs layers we re grown by gas source molecular beam epitaxy on V grooved InP substra tes, with grooves bounded by {211}(A) or {111}(B) facets. The stress f ield associated with the layers was measured by the degree of polariza tion technique, and compared to the predictions of analytical or finit e element models. Good agreement was found for the {211}(A) V grooves, but both the nominally lattice-matched and compressively strained lay ers grown on {111}(B) V grooves displayed similar degree of polarizati on maps. Analytical electron microscopy demonstrated that the {211}(A) V-groove samples had the targeted composition, but the {111}(B) sampl es showed much higher In/Ga ratios at the bottom of the groove than th e expected values. Indium enrichment at the bottom of the groove led t o defect formation there, and left the V groove of both the lattice-ma tched and compressively strained samples under a net compressive force . (C) 1997 American Institute of Physics.