Abstract: A method of doping IIb or VIb group elements into a phosphide semiconductor comprising the steps of adding organic compounds of IIb group elements or hydrides of VIb group elements to a gas containing boron compounds selected from the group consisting of boron hydrides and boron halides and phosphorus compounds selected from the group consisting of phosphorus hydrides and phosphorus halides, in a ratio of 0.05-50 mol of said IIb group organic compounds or 10.sup.-4 -10 mol of said VIb group hydrides per mol of said boron compounds, and conducting vapor phase growing of the boron phosphide semiconductor at a growing temperature between about 850.degree. and 1100.degree. C.