III GROUP NITRIDE SEMICONDUCTOR SUBSTRATE AND METHOD OF MANUFACTURING

摘要

PROBLEM TO BE SOLVED: To provide a III group nitride substrate of which coefficient of thermal expansion is near to that of a III group nitride crystal and which has an excellent crystalline surface to enable the structure of an excellent and thick element layer with less dislocations and the method of manufacturing. SOLUTION: This substrate comprises a polycrystalline III group nitride layer and a monocrystalline nitride formed on it. The monocrystalline III group nitride is grown on a monocrystalline substrate that is soluble in an acid or an alkaline solution and ten the polycrystalline III group nitride is grown. The III group nitride semiconductor substrate is manufactured by growing the monocrystalline III group nitride layer on the monocrystal surface of the nitride substrate after removing the monocrystalline substrate, that is soluble in the acid or the alkaline solution, by the acid or the alkaline solution selectively from group III nitride.