Epitaxial ternary and quaternary III-V antimonide substrates

Modified liquid-phase epitaxy (LPE) techniques can be adapted for the growth of relatively thick (50 to 500 micron) epitaxial layers of ternary and quaternary Ill-V antimonide alloys, including InAsSb, InGaSb, AlGaAsSb, InGaAsSb, and InAsSbP. These structures can function as ´virtual´ substrates with adjustable lattice constants for epitaxy of various optoelectronic devices such as mid-infrared photodiodes. A variety of substrate structures can be realized either by effecting gradual, continuous compositional grading of thick epilayers, or by growing multilayers with abrupt but incremental compositional changes between adjacent layers. Both approaches can be combined with selective removal of the seeding substrate and wafer bonding techniques. Low-defect alloy substrates with increased functionality, and with lattice constants and bandgaps significantly different than available with binary compound wafers (e.g., InAs or GaSb), appear feasible.