ArF excimer laser doping of boron into silicon

Doping of single-crystal silicon in BF₃ ambients using an ArF excimer laser has been investigated as a function of laser fluence, number of pulses and BF₃ gas pressure. From these results, it is found that the surface concentration and the junction depth vary with the number of pulses, and that the doping process is rate limiting. The analysis of the incorporated dose as a function of the pressure suggests that at low gas pressure, the dopant atoms are only supplied from the adsorbed layer whereas at high pressures, the molecules striking the silicon surface are an important dopant supply. It is also shown that at high boron concentration, cracks are produced in the surface region which limit the boron incorporation into silicon. Electrical characteristics of p⁺n junctions which were formed by this technique are reported.