A kind of aln epitaxial layer and preparation method thereof

Abstract

An AlN epitaxial layer and preparation method thereof relate to the field of semiconductor epitaxy technology. According to the invention, an N polarity isolation layer grows at a comparatively low temperature, so that the N polarity is isolated well and single Al polarity is formed. Then a nucleating layer is formed on the N-polarity isolation layer at a medium temperature. The surface transfer ability of Al atoms at the medium temperature is improved and the quality of the nucleating layer is improved. The temperature is increased further and a defect repairing layer is settled on the nucleating layer at a comparatively high temperature, so that spot defect concentration can be reduced in a condition with stress release and dislocation annihilation. Finally, the temperature is increased continually and the high transfer ability of the Al atoms is kept at a high temperature, so that quick settlement on the basis of the defect repairing layer is realized and the growth efficiency is improved. The preparation method provided by the invention is simple in technique, convenient to operate and provides high growth efficiency. The AlN epitaxial layer prepared by adopting the preparation method has characteristics of smooth surface, single Al polarity and low dislocation annihilation.

Description

technical field

[0001] The invention relates to the technical field of semiconductor epitaxy, in particular to an AlN epitaxial layer and a preparation method thereof. Background technique

[0002] In recent years, due to many advantages such as direct bandgap, adjustable bandgap, high temperature resistance, and radiation resistance, AlGaN materials have shown broad application prospects in the fields of optoelectronic devices and electronic devices. From the perspective of growth strain and light transmittance, in order to prepare high-quality AlGaN materials and related devices, the use of AlN homogeneous substrates and AlN / sapphire template substrates is an ideal choice. In the existing technology, due to the lack of low-cost, high-quality, and large-size AlN single crystal substrates, compared with AlN homogeneous substrates, growing AlN templates on cheap and mature sapphire substrates is the mainstream technology in this field route.

[0003] However, at this stage,...

Images