Method for preparing LED (Light-Emitting Diode) with GaN thick film vertical structure

Abstract

The invention provides a method for preparing an LED (Light-Emitting Diode) with a GaN thick film vertical structure. The method comprises the following steps of: preparing a mask pattern on the polished surface of a substrate, wherein the polished surface of the substrate is divided into a plurality of separated areas by the mask pattern to obtain the patterned substrate; depositing an n-type doped GaN thick film on the patterned substrate, wherein the thickness of the GaN thick film is ought to be more than that of the mask pattern; and epitaxially growing a multi-period quantum well LED on the GaN thick film. According to the invention, by means of partitioned growth of the GaN thick film, stresses induced by lattice mismatch and heat mismatch are released, the problem of substrate cracking in secondary epitaxy is solved, the warping degree of the substrate is reduced, and the subsequent processes of laser based substrate stripping and chip manufacturing are facilitated.

Description

technical field [0001] The invention relates to the field of semiconductor light emitting diodes (Light Emitting Diode, LED for short), in particular to a method for preparing a GaN thick film vertical structure LED. Background technique [0002] Aluminum Nitride (AlN), Gallium Nitride (GaN), Indium Nitride (InN) and their alloys are all direct bandgap materials, and the bandgap width is continuously adjustable from 0.7eV (InN) to 6.2eV (AlN) at room temperature , is an ideal material for making blue, green and ultraviolet light-emitting devices. GaN-based LEDs are small in size, long in life, high in efficiency, and do not contain harmful substances such as mercury. They are called a new generation of green and environmentally friendly lighting sources, which are expected to replace traditional incandescent and fluorescent lamps and bring about a revolution in human lighting. [0003] Vertical structure LEDs have very good current spreading performance and heat dissipation...

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Problems solved by technology

[0006] However, when vertical structure LEDs are prepared on GaN thick films, due to the incomplete stress release on the GaN thick films prepared earlier, it is very easy to crack during the second epitaxy. In addition, due to the lattice mismatch between the GaN thick films and the sapphire substrate and Thermal mismatch causes substrate warpage, which brings great difficulties to subsequent chip processes

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