Ultra-shallow high-concentration boron profiles for CMOS processing

The fabrication of ultra-shallow high-concentration boron profiles in silicon has been carried out utilizing a XeCl excimer laser. The Gas Immersion Laser Doping (GILD) process relies on a dopant species, in this case diborane (B2H6), to be adsorbed on the clean silicon surface and subsequently driven in during a melt/regrowth process initiated upon exposure to the short laser pulse. Secondary Ion Mass Spectrometry and spreading resistance profiles show peak boron concentrations from 5 × 10¹⁹cm^-3to 5 × 10²⁰cm^-3depending on the number of laser pulses, with junction depths from 0.08 to 0.16 µm depending on the laser energy. Electrical characteristics show essentially ideal diode behavior following a 10-s 950°C anneal.