DIFFUSION PARAMETERS OF INDIUM FOR SILICON PROCESS MODELING

The diffusion parameters of indium in silicon are investigated. System atic diffusion experiments in dry oxidizing ambients at temperatures r anging from 800 to 1050 degrees C are conducted using silicon wafers i mplanted with indium. Secondary-ion-mass spectrometry (SLMS) is used t o analyze the dopant distribution before and after heat treatment. The oxidation-enhanced diffusion parameter [R. B. Fair. in Semiconductor Materials and Process Technology Handbook, edited by G. E. McGuire (No yes, Park Ridge, NJ, 1988); A. M. R. Lin, D. A. Antoniadis, and R. W. Dutton, J. Electrochem. Sec. Solid-State Sci. Technol. 128, 1131 (1981 ); D. A. Antoniadis and I. Moskowitz, J. Appl. Phys. 53, 9214 (1982)] and the segregation coefficient at the Si/SiO2 interface [R. B. Fair a nd J. C. C. Tsai, J. Electrochem. Sec. Solid-State Sci. Technol. 125, 2050 (1978)] (ratio of indium concentration in silicon to that in sili con dioxide) are extracted as a function of temperature using SIMS dep th profiles and the silicon process simulator PROPHET [M. Pinto, D. M. Boulin, C. S. Rafferty, R. K. Smith, W. M. Coughran, I. C. Kizilyalli , and M. J. Thoma, in IEDM Technical Digest, 1992, p. 923]. It is obse rved that the segregation coefficient of indium at the Si/SiO2 interfa ce is m(In)much less than 1, similar to boron; however, unlike boron, the segregation coefficient of indium at the Si/SiO2 interface decreas es with increasing temperature. Extraction results are summarized in a nalytical forms suitable for incorporation into other silicon process simulators. Finally, the validity of the extracted parameters is verif ied by comparing the simulated and measured SIMS profiles for an indiu m implanted buried-channel p-channel metal-oxide-semiconductor field-e ffect-transistor [I. C. Kizilyalli, F. A. Stevie, and J. D. Bude, IEEE Electron Device Lett. (1996)] process that involves a gate oxidation and various other thermal processes. (C) 1996 American Institute of Ph ysics.