SUBSTRATE-TEMPERATURE DEPENDENCE OF SUBCUTANEOUS OXIDATION AT SI/SIO2 INTERFACES FORMED BY REMOTE PLASMA-ENHANCED CHEMICAL VAPOR-DEPOSITION

We have previously reported that subcutaneous oxidation reactions between process gases and Si surfaces occur during deposition of thin films of SiG2by remote piasma-enhanced chemical vapor deposition (remote PECVD) [G. G. Fountain, S. V. Hattangady, R. A. Rudder, R. I. Markunas, G. Lucovsky, S. S. Kim, and D. V. Tsu, J. Vac. Set Technol. A 7, 576(1989) and G. Lucovsky, S. S. Kim, D. V. Tsu, G. G. Fountain, and R. J. Markunas, J. Vac. Sci. Technol. B 7, 861 (1989)]. We find that the rate of this oxidation process is substrate temperature (Ts) dependent, increasing with increasing Ts. The rate of SiO2deposition by remote PECVD decreases with increasing Tsand the combination of oxide deposition and subcutaneous oxidation serves to establish limits on the deposition temperature, and oxide thickness for gate-quality Si02films on cleaned and characterized Si surfaces. This paper describes the subcutaneous oxidation process, the nature of the oxide films, and the effects of subcutaneous oxidation on interfacial electrical properties of the Si/SiQ2interfaces in metai-oxide-semiconductor (MOS) structures. © 1990, American Vacuum Society. All rights reserved.