Epitaxial growth method of silicon substrate GaN-based LED

Abstract

The invention provides an epitaxial growth method of a silicon substrate GaN-based LED. An LP-MOCVD system of Thomas Swan is adopted, Si (111) is selected as a substrate, TMGa, TMAl, TMIn and high-purity NH3 are respectively sources of Ga, Al, In and N, H2 and N2 are adopted as carrier gases, and SiH4 and CP2Mg are respectively n-type and p-type doping agents; the Si substrate is cleaned before growth to remove pollutants and impurities and obtain a clean surface; and an epitaxial wafer of the silicon substrate GaN-based LED is grown in an epitaxial manner, and the crystallization quality thereof is tested and analyzed by employing DCXRD. It is indicated through a result that the interface of an InGan / GaN multi-quantum well is flat, and the crystallization quality is good; and the period thicknesses of the quantum well, obtained through calculation by employing two methods, are fundamentally consistent.

Description

technical field [0001] The invention relates to a GaN-based LED epitaxial growth method on a silicon substrate. Background technique [0002] Although GaN is an ideal semiconductor device material, there has been a lack of suitable substrates, so good-quality GaN epitaxial layers have not been obtained. Currently, GaN materials used for devices are epitaxially grown through sapphire or SiC substrates. However, these two substrates also have obvious deficiencies. Sapphire is an insulator with high hardness and poor thermal conductivity, making it difficult to process; and SiC is very expensive, which makes the production cost of the device very high. If Si is used as the substrate, it has great advantages over the above two substrate materials, such as large area, low cost, high quality, good electrical and thermal conductivity, etc. Therefore, the research on the growth of GaN thin films on Si substrates has received extensive attention. However, there are still many diffi...

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Problems solved by technology

However, there are still many difficulties in using Si as the substrate. There is a large lattice mismatch between the GaN epitaxial layer and Si crystal, which causes a large number of dislocations in the epitaxial layer; there is also a large thermal mismatch between GaN and Si crystal. At the end of the reaction, from high temperature to room temperature, this thermal mismatch will generate a huge tensile stress in the epitaxial layer, which will cause cracks in the epitaxial wafer.

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