The Properties Of GaN-based LED On Metal Substrate By Electroplating Grown On Si Substrate

GaN-based LED has been widely used in various fields of society and formed a huge market, many countries launched solid-state lighting program, so reserch and develop power-type chip is very imperative. Compared with the other two substrates, silicon material has low cost, large size, high crystal quality, easy processing, good electrical conductivity and thermal conductivity, furthermore easy to transfer GaN epilayers to a new substrate and then obtain a vertical structure devices which have better performance. Electroplating is a mature, low-cost, simple, convenient controllability technology, and can avoid high temperature. Which combined electroplating to technology of GaN epitaxial on Si substrate is expected to obtain a higher cost performance on power type LED applications. In this paper, GaN thin film were successfully transferred from Si substrate via electroplating and chemical corrosion to metal substrates the first time, after chip process we obtain the vertical structure light-emitting device. This paper had a study on current and ambient temperature impact on the device performance; comparated the aging performance of Cu substrate devices and CuCr substrate devices via electroplating and chemical etching with Si substrate devices via bonding and chemical etching; had a research on the GaN epilayers'stress change before and after transferring to the three kinds of new substrates; tested the junction temperature of three kinds of sample under different operating current, and received some research results:The chips with metal substrate have good performance dependence of temperature and current, which attribute to the good crystal quality, the good thermal conductivity and reasonable structure of epitaxy of the samples;After transferring the GaN epilayers to Si substrate, CuCr substrate via electroplating, bonding and chemical etching, the tensile stress which GaN suffered were still exist,but the tensile stress decreasesed more than the epitaxy wafer, and the tensile stress of CuCr substrate samples was smaller than the Si substrate sample, after transferring to Cu substrate, GaN sufferred tensile stress changed to compressive stress;Compared with samples of Si substrate and the samples of CuCr substrates, Cu substrates have the best aging properties under the same aging conditions, which due to GaN epitaxial film stress release more thorough of the samples of Cu substrate and the good thermal conductivity of Cu substrate;Compared with samples of CuCr substrates and samples of Si substrate, Under the same operating current, and, Cu substrate, the samples of Cu substrate have the minimum junction temperature, which because of the highest thermal conductivity of Cu substrate.This paper Supported by Program for Changjiang Scholars and Innovative Research Team in University(IRT0730) and National High Technology Research Development Program (IRT0730)...