OPTIMIZED SIO2 INP STRUCTURES PREPARED BY ELECTRON-CYCLOTRON-RESONANCE PLASMA/

A fabrication procedure for high quality SiO2/InP structures has been developed using electron cyclotron resonance plasmas. The oxidation of InP in an oxygen plasma was investigated by x-ray photoelectron spect roscopy (XPS) to prepare an appropriate interfacial layer made of a si ngle phase native InP oxide. Silicon dioxide films were prepared on In P (100), using SiH4 and oxygen plasma. We studied the effect of plasma parameters (substrate temperature, flow rates, flow rate ratio, chamb er pressure, and annealing conditions) on the structural and electrica l properties of the films. The SiO2 films and the SiO2/InP interface w ere characterized in situ by XPS and ex situ by spectroellipsometry. E lectrical C-V and I-V measurements were performed on metal-insulator-s emiconductor structures. The films are stoichiometric for deposition t emperatures ranging from 150 to 300 degrees C, with bulk properties ve ry close to those of thermally grown silicon dioxide. Optimized SiO2/I nP structures, with an interface state density of 10(11) cm(-2) eV(-1) and a long term drift that is lower than 0.2 eV after 10(3) s of stre ss under 4 V in accumulation, are obtained for a deposition temperatur e of 200 degrees C and with a 10 Angstrom thick single phase native ox ide prepared in indirect plasma conditions. It was found that the elec trical interfacial properties of the SiO2/InP structures are directly correlated to their interfacial chemistry. (C) 1996 American institute of Physics.