Formation of Ge pn-junction diode by phosphorus doping with liquid immersion laser irradiation

We examined the formation of pn-junction didoes on Ge(100), Ge(110), and Ge(111) substrates by P-doping with immersion laser irradiation in phosphoric acid solution at RT. We achieved high-concentration phosphorus doping in all orientation, and the maximum concentrations of electrically activated P of 2.4×1019, 5.1×1019, and 9.8×1019 cm−3 for the Ge(100), Ge(110), and Ge(111) substrates, respectively, are obtained with 1000-times laser shots. On the other hand, the diffusion depth is significantly different with the orientation, which concerned with the melt depth.