| 摘要 |
PURPOSE:To enable to form an electrode on both upper and lower surfaces by a method wherein excellent GaN is formed on a sapphire substrate using Al as a buffer layer, the AlN is selectively removed by dissolution, and the GaN is exfoliated. CONSTITUTION:AlN is grown on a sapphire substrate by the reaction of (CH3)3 Al and NH3 at 1,200 deg.C using an MOCVD method. Besides, n-GaN 2 is grown by the reaction of (CH3)3Ga and NH3 at 950 deg.C, Zn is added, and an insulative GaN 3 is superposed thereon. The lattice mismatching of the supphire and GaN is great, but a GaN of excellent crystallizability can be obtained through the intermediary of an AlN layer. Then AlN is selectively removed by dissolution by dipping into voiled water, for example, and exfoliated from sapphire, and an Al vapor-deposited electrodes 4 and 10 are formed on the upper and the lower surfaces. According to this constitution, an electrode can be formed on the upper and the lower surfaces of the GaN, whereon a chemical etching and a mechanical work for formation of an aperture are difficult, and a GaN device can be formed using th ordinary wire bonding technique, thereby enabling to sharply increase productivity. |
