Macrolattice mismatch epitaxial buffer layer structure containing digital dislocation separating layers and preparation method thereof

Abstract

The invention relates to a macrolattice mismatch epitaxial buffer layer structure containing digital dislocation separating layers and a preparation method thereof. The structure is characterized in that n layers of digital alloy dislocation separating layer materials are inserted into an ingredient gradual changing buffer layer. The preparation method comprise the following steps: adjusting beam source temperature, growing a ingredient gradual changing buffer layer on a substrate, and according to present gradual changing ingredient, forming a digital alloy dislocation separating layer through growing short period superlattice; adjusting the beam source temperature again, growing a ingredient gradual changing buffer layer, regrowing a digital alloy dislocation separating layer according to present gradual changing ingredient; regrowing a ingredient gradual changing buffer layer in above sequence until the buffer layer ingredient gradually changes to a desirable value to obtain the macrolattice mismatch epitaxial buffer layer structure. According to the invention, the macrolattice mismatch epitaxial material takes place relaxation and releases stress rapidly and effectively in the buffer layer and isolates penetrating dislocation, thus penetrating dislocation density of the epitaxial material on the buffer layer is reduced, and crystal lattice quality and photoelectric characteristic of the macrolattice mismatch epitaxial material on the buffer layer are improved.

Description

technical field [0001] The invention belongs to the field of large lattice mismatch epitaxy materials and preparation thereof, in particular to a large lattice mismatch epitaxy material buffer layer structure containing a digital alloy dislocation isolation layer and a preparation method thereof. Background technique [0002] With the development of semiconductor energy band engineering and the advancement of material epitaxy technology, more and more attention has been paid to heteroepitaxy materials with a lattice mismatch with the substrate. When a lattice-mismatched material is epitaxially grown on a substrate, when the mismatched epitaxial layer is sufficiently thin, the lattice constant of the epitaxial layer will be compatible with the lattice of the substrate under the action of the deformation energy generated by the lattice mismatch. The constants are kept consistent to avoid dislocations. However, when the epitaxial thickness exceeds a certain thickness (called c...

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Problems solved by technology

[0005] The technical problem to be solved by the present invention is to provide a large lattice mismatch epitaxial material buffer layer structure containing a digital alloy dislocation isolation layer and its preparation method. The material contains a digital alloy dislocation isolation layer, which can make the large lattice The matching epitaxial material relaxes quickly and effectively in the buffer layer to release the stress, and isolates the threading dislocations, thereby reducing the threading dislocation density of the epitaxial material on the buffer layer and improving the efficiency of the large lattice mismatch epitaxial material on the buffer layer. Excellent lattice quality and photoelectric properties, and overcome the shortcomings of traditional strain-compensated superlattice dislocation isolation layers with small bandgap width and complicated parameter adjustment

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