Method for preparing semi-polar AlN template

Abstract

The invention discloses a method for preparing a semi-polar AlN template. The method comprises: an AIN (101-1) or (101-3) twin crystal structure is generated by induction during an AIN growth process and thus the AIN growth orientation is changed to be [101-1]; and then a semi-polar AlN template is obtained. With the method, the c-surface sapphire or SiC material is selected directly to make a substrate and thus no r-surface sapphire is needed, so that the fault in an AIN epitaxial layer can be reduced and the cost is low. At the initial stage of the AIN growth, a (101-1) or (101-3) twin crystal structure is generated by induction and the AIN growth orientation is changed from [0001] to [101-1], so that the growth window becomes wide and the growth condition is easy to control. Meanwhile, the AIN can grow along a [101-1] semi-polar direction subsequently only by one-step growth and no growth condition needs to change, so that secondary pollution can be avoided and thus a high-quality semi-polar AlN template can be obtained.

Description

technical field [0001] The invention particularly relates to a method for preparing a semipolar AlN template, which belongs to the field of material science. Background technique [0002] The forbidden band of AlN and its alloys with hexagonal wurtzite structure covers the ultraviolet spectral range of 200-365nm, which is an ideal material for the preparation of deep ultraviolet optoelectronic devices and high-frequency and high-power devices. However, AlN-based materials are usually grown along the polar axis—c-axis, so that AlN and its alloys have strong spontaneous and piezoelectric polarization in the [0001] direction. This polarization effect will generate a high-intensity built-in electric field in the nitride epitaxial layer, causing the energy band to bend and tilt, so that electrons and holes are separated in space, which greatly reduces the luminous efficiency of AlN-based optoelectronic devices. Therefore, people try to improve the performance of light-emitting d...

AI Technical Summary

Problems solved by technology

However, the size of AlN materials obtained by this method is very limited, which forces researchers to try to epitaxially semipolar AlN materials on non-c-plane heterogeneous substrates such as sapphire and silicon carbide, but this technique is very difficult. Moreover, the crystal quality of AlN is poor and the dislocation density is high, which seriously restricts the efficiency of AlN-based optoelectronic devices.

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