| 摘要 |
PURPOSE:To effect control properly for the realization of a stable low impurity concentration by a method wherein Si is used as an donor impurity, the reaction temperature and carrier gas flow are regulated to control the quantity of Si, the reaction of Si and NH3 is used to keep Si as an impurity at low concentration, and growth is accomplished in an argon gas atmosphere wherein the Si impurity level is lowered. CONSTITUTION:A GaP substrate, Ga, and polycrystalline GaP are separately set on a quartz board, and hydrogen gas is purged into a reaction tube. Temperature is caused to rise under the ambient pressure. The board is kept at 1000 deg.C for a prescribed period, whereby the polycrystalline GaP melts into the Ga solution and, owing to the reducing reaction of H2 gas, Si melts out of the quartz board into the Ga solution. The Ga solution is placed on the GaP substrate, after which temperatures is lowered to 950 deg.C, when an n-type GaP layer 11 (carrier concentration: 2X10<17>cm<-3> or lower) grows. The carrier H2 is replaced with a gas mixture Ar+NH3 and, after a prescribed period of time, the carrier gas is replaced with Ar. A process follows wherein the temperature is lowered to 900 deg.C, when an n<->-type GaP layer 12 (carrier concentration: approximately 1X10<16>cm<-3>) grows. Next, with the temperature kept at 900 deg.C, Zn is heated and vaporized, and the acceptor impurity is introduced into the main furnace. After a prescribed length of time, the temperature is allowed to lower to 750 deg.C, where a P-type GaP grown layer 13 materializes. |
