Alpha-Ga2O3 Semiconductor Film with Gradient Buffer
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Solution Overview
Problem
Power semiconductors require high withstand voltage characteristics, but existing methods, such as using a buffer layer, result in insufficient dielectric breakdown electric field characteristics due to high crystal defects in α-Ga2O3 semiconductor films grown on sapphire substrates.
Innovation Solution
A semiconductor film with a corundum-type crystal structure composed of α-Ga2O3 or its solid solution, where the impurity concentration and/or heterogeneous phase amount differs between the front and rear surfaces, significantly reducing crystal defects and enhancing dielectric breakdown electric field characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a buffer layer is introduced between sapphire and α-Ga2O3 layer, then crystal defects in α-Ga2O3 are reduced, but dielectric breakdown electric field characteristics remain insufficient
Solution Approach 1:
The patent applies parameter changes by creating a gradient composition in the buffer layer where the Al content varies continuously from the sapphire interface to the α-Ga2O3 interface. This gradual compositional transition allows for progressive lattice matching, reducing crystal defects while maintaining high dielectric breakdown characteristics. The buffer layer composition is specifically designed to change parameters (Al concentration, thickness) to optimize both defect reduction and electrical performance.
Solution Approach 2:
The patent uses composite materials by creating a multi-layer structure consisting of sapphire substrate, gradient (Alx,Ga1-x)2O3 buffer layer, and α-Ga2O3 layer. The buffer layer itself is a composite with varying composition, combining Al2O3 and Ga2O3 in different proportions to achieve intermediate lattice constants that bridge the mismatch between sapphire and α-Ga2O3, thereby reducing defects while preserving electrical characteristics.
2Stability of the object's composition
If heteroepitaxial growth is used to form single-crystal α-Ga2O3 on sapphire substrate, then single-crystal structure is achieved, but large number of crystal defects are generated due to lattice mismatch
Solution Approach 1:
The patent introduces a gradient composition buffer layer as an intermediary between the sapphire substrate and the α-Ga2O3 layer. This buffer layer acts as a mediator that gradually transitions the lattice constant from the sapphire value to the α-Ga2O3 value, reducing the abrupt lattice mismatch. The buffer layer composition is designed to create a smooth transition zone that minimizes dislocation generation while maintaining single-crystal growth of the α-Ga2O3 layer.
Data Source
AI summary
Provided is a semiconductor film having a corundum-type crystal structure composed of α-Ga2O3 or an α-Ga2O3 solid solution, and an impurity concentration and/or a heterogeneous phase amount differ between a front surface and a rear surface of the semiconductor film.