Liquid Phase Epitaxial Growth of GaInp Alloy Thick Layer and its Application

点击翻译按钮获取中文摘要

GalnP alloy is a promising material for green-light-emitting devices. However, the devices made from the alloy have not yet been fabricated by industrial manner. A large obstacle is the absence of the substrate to grown the alloy on. In this study, a technique to prepare an alloy bulk or a thick layer available to the the substrate was developed.To obtain a thick grown layer, a liquid phase growth technique was adopted. Three problems to be solved are 1) escape of P from the growth solution due to evaporation, 2) the substrates for the growth of the alloy ; the substrates cannot be obtained in this stage, and 3) the method to grow a sufficiently thick alloy, which can not be achieved by a conventional slow cooling method. The experimental results are as follows. 1) A quasi-air-tight slide boat was used. The growth rate could be increased as compared with the cases using the conventional open-type boat. 2) Two kinds of substrate were adopted ; GaAsP expensive substrates and GaP substrates used widely. A lattice mismatch exists between a GaP substrate and a grown alloy layer. To relax the mismatch, the fabrication of a step-wise graded composition layer and a continuously graded one on the GaP substrate was investigated. It was made clear that the compositional step of 0.25 mole fraction can be allowed for a layer-mode growth under suitable conditions. In the experiments for the continuously graded composition, the composition could be changed from 0.95 to 0.61 by slow-cooling method. 3) The yo-yo solute feeding method was applied to the growth of a thick layer, and the layer with 200mum thickness could be successfully grown on the GaP substrate. Using 1), 2) and 3) techniques mentioned above, GaInP alloy substrates can be fabricated. Thus, the fundamental techniques to develop a high efficiency greenlight-emitting diode could be established.