A kind of aluminum nitride epitaxial structure and growth method thereof

Abstract

The invention discloses an aluminum nitride epitaxial structure. The structure comprises a nano patterned sapphire substrate, an aluminum nitride (AlN) nucleating layer, a quasi-two-dimensional structure layer, a three-dimensional structure layer, a three-dimensional-to-two-dimensional rapid switching layer and a two-dimensional structure layer, wherein the quasi-two-dimensional structure layer isa 2D-morphology aluminum nitride layer of a net structure, the three-dimensional structure layer is a 3D-morphology aluminum nitride layer, the three-dimensional-to-two-dimensional rapid switching layer is a 2D-morphology aluminum nitride layer, and the two-dimensional structure layer is a 2D-morphology aluminum nitride layer. The invention further provides a growth method of the aluminum nitrideepitaxial structure. In an AlN epitaxial growth process, an AlN epitaxial layer with a smooth and flat surface can be obtained by adopting a high temperature-low temperature-pulsed ammonia gas-high temperature four-step growth method and through regulating and controlling temperature and V / III in the AlN growth process and on the basis of a pulsed ammonia gas lateral epitaxial growth technology,and therefore, the dislocation density of the epitaxial layer is effectively reduced, the crystal quality of the AlN epitaxial layer is improved, and the internal quantum efficiency of an ultravioletlight-emitting diode is improved.

Description

technical field [0001] The invention relates to the technical field of semiconductor light-emitting diodes, in particular, the invention relates to an aluminum nitride epitaxial structure and a growth method thereof. Background technique [0002] Aluminum nitride (AlN) has the advantages of high band gap, high thermal conductivity and strong radiation resistance, and is widely used in ultraviolet light-emitting diode (UV LED) devices. Since the lattice constant and thermal expansion coefficient of AlN crystal and GaN crystal are relatively close, the lattice mismatch between sapphire and gallium nitride (GaN) materials can be reduced, and the crystal quality of epitaxially grown AlGaN can be improved, thereby improving the photoelectric performance of UV LEDs. However, the lattice constant and thermal expansion coefficient of the sapphire substrate and the AlN material are large, and there is still a large lattice mismatch, which will introduce a large dislocation density an...

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Problems solved by technology

Growth of AlN epitaxial layer on nano-patterned sapphire substrate (NPSS) can make up for the lack of lateral growth and migration ability of AlN. High temperature growth is conducive to two-dimensional growth of AlN, but AlN is easy to grow in the pit of NPSS during high temperature growth. It is not conducive to the lateral growth and merging of grid-like AlN epitaxial layers

And after growing AlN at a low temperature to form a three-dimensional shape, it directly enters the high-temperature growth stage, and it is difficult to obtain a smooth and flat AlN epitaxial layer.

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