Epitaxial substrate for high-intensity led, and method of manufacturing

Abstract

An epitaxial layer having a double-hetero structure is forming using an MOCVD process or an MBE process, and an epitaxial substrate is formed using an LPE process, thereby forming a substrate which exploits the distinguishing features of both processes. Since the MOCVD process or MBE process exhibits mixed-crystal ratio and film thickness controllability, excellent reproducibility and uniformity are obtained when forming the double-hetero structure on a compound semiconductor substrate. Since the growth process takes place under thermal non-equilibrium, the amount of impurity doping is raised to more than 10.sup.19 cm.sup.3. This is advantageous in terms of forming an electrode contact layer. With the LPE process, the material dissolved in the melt is grown epitaxially on the substrate by slow cooling, and the rate of growth is high. This process is suitable for forming the substrate after removal of the compound semiconductor substrate. By virtue of this liquid phase epitaxy, an oxide film preventing layer is removed by raising the degree of unsaturation of the melt, the epitaxial layer is grown in a short period of time, and a high-quality, highly uniform epitaxial substrate can be quickly manufactured. It is also possible to reduce cost.