Patent ID: 8129208

Claim:
A method of manufacturing an n-type conductive aluminum nitride semiconductor crystal containing Si atom at a concentration of 1×10 18 to 5×10 20 cm −3 , wherein the semiconductor crystal has an absorption coefficient for light having an energy of not less than 1.59 ev and not more than 5.9 ev of not more than 5,000 cm −1 , and wherein an halogen atom content in the semiconductor crystal is not more than 5×10 18 cm −3 , the method comprising the steps of: (A) forming an aluminum nitride crystal layer having a thickness of not less than 0.5 nm on a single crystal substrate by vapor-phase growing, wherein a temperature of the substrate is 1,000 to 1,150° C., and wherein the heated single crystal substrate is contacted with a gas containing an Al halide and a nitrogen-containing compound to form an AlN crystal, and (B) preheating the obtained substrate having the aluminum nitride crystal layer on its surface to 1,200° C. or more, then forming an n-type conductive semiconductor crystal layer on the aluminum nitride crystal layer of the substrate by vapor-phase growing in which the preheated substrate is contacted with a gas containing an Al halide, a nitrogen-containing compound and a compound represented by the formula SiH x Cl 4-x wherein, x is an integer of 0 to 3, to form the n-type conductive aluminum nitride semiconductor crystal doped with Si atom.