Application of flash-assist rapid thermal processing subsequent to low-temperature furnace anneals

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 1×1015cm−2 and then implanted with 1keV, 1×1015cm−2 B. Low-temperature furnace anneals are performed at 500°C for 30min and the wafers subsequently subjected to flash-assist RTP anneals in the range 1000–1300°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 mobi...