Abstract: In a method of making a flip-chip bonded GaAs-based opto-electronic device, removal of the GaAs substrate is facilitated by provision of a lattice matched (Al.sub.x Ga.sub.1-x)InP etch stop layer, exemplarily a Ga.sub.0.51 In.sub.0.49 P layer, and use of an etchant that isotropically etches GaAs such that an essentially mirror-like etch stop layer surface results, and that preferably exhibits an etch rate ratio of at least 200:1 for GaAs and the etch stop layer, respectively. Use of the novel substrate removal method can substantially increase device yield, and facilitate manufacture of large device arrays, e.g., arrays of detector/modulator diodes flip-chip bonded to Si CMOS chips.

Abstract: In a DH-PHEMT the channel layer comprises InGaAs and the donor layers comprise In.sub.0.5-q (Al.sub.x Ga.sub.1-x).sub.0.5+q P in which the mole fraction of Al is in the range of about 0.2.ltoreq.x.ltoreq.0.3. In another embodiment, an InAlGaP layer forms a Schottky barrier gate contact with a barrier height of about 1.0 eV and hence low leakage current. The devices exhibit high 2DEG density, current drivability, and breakdown voltage, making them suitable for low voltage application such as battery-powered, portable wireless equipment. The Schottky barrier contact may be used in devices other than HEMTs.

Abstract: In a DH-PHEMT the channel layer comprises InGaAs, the donor layers comprise In.sub.y Ga.sub.1-y P(0.15.ltoreq.y.ltoreq.0.85), and each of the spacer layers comprises an In.sub.0.5-q (Al.sub.x Ga.sub.1-x).sub.0.5+q P outer spacer layer (0.2.ltoreq.x) and an Al.sub.r Ga.sub.1-r As (0.ltoreq.r.ltoreq.0.3) inner spacer layer. In another embodiment, a similar InAlGaP layer forms a Schottky barrier gate contact with a barrier height of at least 1.0 eV and hence low leakage current. The devices exhibit the capability for both low noise and high power operation at low supply voltages.