III-N Semiconductor Growth on Silicon via Rare Earth Oxide Buffer
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Solution Overview
Problem
Growing III-N semiconductor materials on silicon substrates is challenging due to significant crystal lattice mismatch and thermal expansion differences, leading to strain and stress issues, which prior buffer layers fail to adequately address.
Innovation Solution
The method involves growing a layer of epitaxial rare earth oxide on a silicon substrate, modifying its surface with nitrogen plasma to create a nitrogen atom template, and then growing low temperature gallium nitride and bulk III-N semiconductor material, utilizing a stress-induced nitridized rare earth oxide layer to reduce strain and facilitate thick, stress-free epitaxial growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a III-N material is grown on a silicon substrate, then cost efficiency is improved, but crystal quality deteriorates due to large lattice mismatch and thermal expansion difference
Solution Approach 1:
A rare earth oxide (REO) buffer layer is introduced as an intermediary between the silicon substrate and the III-N material. This REO layer serves as a mediator that reduces the lattice mismatch stress and thermal expansion difference, enabling high-quality III-N crystal growth on silicon substrates while maintaining cost efficiency
Solution Approach 2:
The patent uses a composite structure consisting of multiple layers: silicon substrate, REO buffer layer, and III-N material layer. This composite approach combines materials with different properties to overcome the limitations of direct growth, achieving both cost efficiency and high crystal quality
2Stability of the object's composition
If a buffer layer is formed on the silicon substrate, then strain reduction is improved, but device complexity increases
Solution Approach 1:
The patent changes the material parameter by using rare earth oxide with specific lattice constants that are intermediate between silicon and III-N materials. This parameter selection optimizes strain reduction while keeping the buffer layer structure relatively simple
Solution Approach 2:
The REO buffer layer performs multiple functions simultaneously: it reduces lattice mismatch strain, manages thermal expansion differences, and provides a suitable template for III-N material growth. This multi-functionality reduces the need for additional complex buffer structures
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables the growth of single crystal III-N semiconductor layers with reduced stress and fractures, allowing for the formation of high-quality semiconductor devices like LEDs, by leveraging the lattice matching and stress relief provided by the rare earth oxide and nitrogen plasma treatment.
Implementation Method 1
modifying its surface with nitrogen plasma
Implementation Method 2
modifying the surface of the layer of epitaxial rare earth oxide with nitrogen plasma
Implementation Method 3
growing a layer of epitaxial rare earth oxide on a single crystal silicon substrate
Data Source
AI summary
A method of growing III-N semiconducting material on a silicon substrate including the steps of growing a layer of epitaxial rare earth oxide on a single crystal silicon substrate and modifying the surface of the layer of epitaxial rare earth oxide with nitrogen plasma. The method further includes the steps of growing a layer of low temperature epitaxial gallium nitride on the modified surface of the layer of epitaxial rare earth oxide and growing a layer of bulk epitaxial III-N semiconductive material on the layer of low temperature epitaxial gallium nitride.