AbstractOne alternative to conventional rapid thermal annealing (RTA) of implants for ultra-shallow junction formation is that of laser annealing. Laser thermal processing (LTP) incorporates an excimer pulsed laser capable of melting the near surface region of the silicon (Si) substrate. The melt depth is dependent upon the energy density supplied by the irradiation source and the melting temperature of the substrate surface. A process window associated with this technique is able to produce similar junction depths over a range of energy densities due to the melting temperature depression established with pre-amorphization of the substrate surface prior to dopant incorporation. The process window of germanium (Ge) preamorphized, boron (B) doped Si was investigated. 200 mm (100) n-type Si wafers were preamorphized via 18 keV Ge+ implantation to 1x1015/cm2 and subsequently implanted with 1 keV B+ to doses of 1x1015/cm2, 3x1015/cm2, 6x1015/cm2, and 9x1015/cm2. The wafers were laser annealed from 0.50 J/cm2 to 0.88 J/cm2 using a 308 nm XeCl excimer irradiation source. Transmission electron microscopy (TEM) was used to determine the process window for each implant condition, and correlations between process window translation and impurity concentration were made. Four-point probe quantified dopant activation and subsequent deactivation upon post-LTP furnace annealing.
