EFFECTS OF SULFIDE PASSIVATION ON THE PERFORMANCE OF GAAS MISFETS WITH PHOTO-CVD GROWN P3N5 GATE INSULATORS

Accumulation-mode and depletion-mode GaAs metal-insulator-semiconducto r field-effect transistors (MISEETs), with sulfur-treatment and a phot ochemical vapor-deposited-P3N5 gate insulator, have been successfully fabricated. The devices have good linearity, low hysteresis in current -voltage characteristics, and the instability of the current less than 22 percent for the period of 1.0-1.0 x 10(4) s. The effective electro n mobility and extrinsic transconductance of the FETs at room temperat ure are about 1300 cm(2)/V . s and 1.41 mS/mm for the accumulation-mod e, and about 4500 cm(2)/V . s and 4 mS/mm for the depletion-mode, resp ectively. Capacitance-voltage (C-V) characteristics and Anger electron spectroscopy (AES) analysis for different sulfur-treatment conditions are discussed. The atomic concentration ratios of sulfur and oxygen t o arsenide oil GaAs surfaces and GaAs metal-insulator-semiconductor (M IS) interface properties are critically dependent on sulfur pretreatme ent conditions, and the optimum sulfur-treatment temperature is determ ined to be about 40 degrees C. The minimum density of interface trap s tates for an Al/P3N5/GaAs MIS diode with the optimized surface treatme nt is about 4.3 x 10(10) cm(-2) eV(-1).