A review of rapid thermal annealing (RTA) of B, BF 2 and As ions implanted into silicon

Abstract RTA studies of B, BF 2 and As implantations in silicon are reviewed. The optical coupling properties of the wafer are considered as a motive for obtaining accurate temperature assessment. Optical pyrometer techniques with feedback control are now commonly used. Enhanced diffusion of boron is widely reported for the channel tail in the several second time frame at ∼1050°C. Boron diffusion in preamorphized and crystalline silicon are compared, and dopant interactions (gettering) with residual disorder located just beyond the amorphous/crystalline (α/c) interface are discussed. The removal of residual α/c disorder from a 5 × 10 15 As/cm 2 , 100 keV implant is shown to occur with ∼5.0 eV energy, while a “normal” concentration enhanced diffusion with ∼4.0 eV activation energy is obtained including data in the several second (RTA) time frames. Shallower defect free arsenic junctions are made using high temperature-short time cycles, rather than longer times at lower temperatures. The arsenic diffusion issues are discussed.