SUBSTRATE TREATED TO FORM SINGLE CRYSTAL ON SURFACE AND PREPARATION THEREOF

摘要

PURPOSE:To prepare inexpensively a substrate treated to form single crystals of uniform quality on the surface by forming plural numbers of island parts separately to each other on the surface of a molded body of powdery starting material which is to form duplex structure by calcination, then calcining the substrate by normal calcination. CONSTITUTION:A molded body having a specified shape which will have a duplex structure of a desired density when it is calcined normally at a specified temp. is prepd. by molding powdery starting material such as alumina in a mold. Then, the molded body is calcined preliminarily at lower temp. than the normal calcination temp. by 50-500 deg.C, and grooves 3 are then formed with a diamond cutter, etc. on the surface of the molded body to form plural numbers of island parts 2 separated to each other. The molded body is then calcined normally at specified temp. to obtain a substrate comprising a surface side comprising single crystals formed completely to one giantic crystal as a whole from each island part, and a rear surface side consisting of polycrystalline part 1 of the starting material powder.