insulated gate electronic devices on inp and related iii-v compound semiconductors have not to date achieved a level of performance adequate for commercial exploitation. this in part is believed to be due to the noncongruent dissociation of the group v element upon heating. in order to minimize such surface effects on inp, the authors have investigated two broad approaches: one involving the creation of an excess overpressure of phosphorus to suppress the anion loss: and one involving the creation of an ideal interface analogous to the sio/sub 2//si system by sulfurization. in situ photoluminescence, measured during annealing in a phosphorus ambient in a mass spectrometer equipped low-pressure chemical vapor deposition growth chamber, shows that surface degradation may be retarded by appropriate use of gaseous phosphorus. a phosphorus-rich interfacial oxide, grown prior to sio/sub 2/ growth, similarly appears to considerably improve the interface of inp metal-insulator-semiconductor (mis) structures as seen by c-v analysis. sulfurized inp mis structures treated in (nh/sub 4/)/sub 2/s/sub x/, show excellent interface quality as judged by high-frequency and quasistatic c-v measurements. mis field effect transistors fabricated using the benefits of these surface treatments show large transconductances and stabilities approaching those of thermal sio/sub 2//si with <5 percent variation in drain current over a 12 h test period