Application of flash-assist rapid thermal processing subsequent to low-temperature furnace anneals
Camillo-Castillo, RA × Law, ME Jones, KS Lindsay, R Maex, Karen Pawlak, BJ McCoy, S #
A v s amer inst physics
Journal of vacuum science & technology b vol:24 issue:1 pages:450-455
The substantial reductions in anneal times, such as in flash-assist rapid thermal processing (fRTP), place considerably more emphasis on the initial condition of the wafer, which may assume a greater role in the dictating diffusion product (Dt). Investigations have been conducted on the effect of low-temperature preanneals prior to fRTP on the extended defect nucleation and evolution and on boron activation. Czochralski grown n-type silicon wafers are preamorphized with 8 Ge+ ions at a constant dose of 1 X 10(15) cm(-2) and then implanted with 1 keV, 1 X 10(15) cm(-2) B. Low-temperature furnace anneals are performed at 500 degrees C for 30 min and the wafers subsequently subjected to flash-assist RTP anneals in the range 1000-1300 degrees C. Four-point probe measurements indicate that the low-temperature anneal results in higher sheet resistance values. Plan-view transmission electron microscopy, secondary-ion-mass spectrometry, and Hall-effect measurements revealed no substantial differences in defect structure, junction depth, or mobility. However, the carrier density was found to be higher for those wafers which were preannealed. (c) 2006 American Vacuum Society.