| 摘要 |
PURPOSE:To realize a boron doping with good controllability and high concentration in the use of a conventional cell, by irradiating a substrate with molecular beams, which are obtained by heating B2O3 or a mixture containing B2O3, when a semiconductor thin film is formed on the substrate by a molecular-beam epitaxial method. CONSTITUTION:A boron doping can be realized within a usual heat-resisting temperature range (-1,400 deg.C) of a PBN kiln, with B2O3 serving as doping blank material. As compared with a gallium doping which has been performed as a P-type doping by silicon molecular-beam epitaxial growth so far, the boron doping has the following advantages; the doping with high concentration of 8X10<18>cm<-3> can be realized, and besides an epitaxial film of good quality having very few lattice defects is obtained. The doping amount never varies with substrate temperature. A very sharp impurity profile can be obtained merely by opening and closing a cell shutter, even during growth at low temperature under 800 deg.C. |
