Nitride Semiconductor Layer Growth on Silicon With Stress Compensation
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Solution Overview
Problem
Existing methods for producing nitride semiconductor components on silicon substrates face challenges such as high tensile stress, dislocation concentration, and substrate curvature, leading to increased production costs and reduced component lifespan due to crack formation and mechanical instability.
Innovation Solution
A process involving the deposition of an aluminium-containing nitride nucleation layer, optional buffer layer, and a masking layer, followed by a gallium-containing nitride semiconductor layer, where crystallites coalesce to form an average surface area of at least 0.16 μm², generating a compressive stress that compensates for tensile stress and reduces substrate curvature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If nitride semiconductor layers are grown on silicon substrates at high temperatures (above 1000°C), then the growth quality and crystalline structure are improved, but high tensile stress develops due to thermal expansion mismatch leading to crack formation
Solution Approach 1:
A silicon nitride (SiN) intermediate layer is inserted between the silicon substrate and the nitride semiconductor layer. This intermediate layer acts as a stress buffer that compensates for the tensile stress generated by thermal expansion mismatch during cooling, preventing crack formation while allowing high-temperature growth of high-quality layers
Solution Approach 2:
The thickness of the silicon nitride intermediate layer is optimized to achieve complete stress compensation. By adjusting this parameter, the tensile stress in the nitride semiconductor layer is reduced to nearly zero, preventing crack formation while maintaining layer quality
2Strength
If thin intermediate layers are used to prevent crack formation, then mechanical stability is improved, but dislocation concentration increases significantly
Solution Approach 1:
The thickness of the silicon nitride intermediate layer is precisely optimized to balance two competing requirements: it must be thick enough to compensate tensile stress and prevent cracks, but thin enough to minimize dislocation generation. The patent determines the optimal thickness range to achieve complete stress compensation while keeping dislocation density low
3Productivity
If large-area silicon substrates are used for cost-effective production, then productivity and cost efficiency are improved, but substrate curvature increases due to stress accumulation
Solution Approach 1:
The silicon nitride intermediate layer serves as a stress buffer that compensates for tensile stress across the entire substrate area. By inserting this intermediate layer, the patent enables the use of large-area silicon substrates without excessive curvature, maintaining substrate flatness while achieving cost-effective large-area production
4Manufacturing precision
If conventional substrate materials like sapphire or silicon carbide are used, then layer growth quality is improved, but production cost increases due to substrate expense and processing difficulty
Solution Approach 1:
The patent replaces expensive sapphire or silicon carbide substrates with inexpensive silicon substrates. Although silicon has thermal expansion mismatch issues, the use of a thin silicon nitride intermediate layer resolves this problem, enabling cost-effective production while maintaining layer growth quality
Solution Approach 2:
The silicon nitride intermediate layer enables the use of cheap silicon substrates by compensating for thermal expansion mismatch. This intermediate layer makes silicon substrates suitable for high-quality nitride semiconductor growth, achieving both cost reduction and maintained manufacturing precision
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
The process results in nearly stress-free or low-stress nitride semiconductor layers with reduced dislocation density, enabling cost-effective production of large-area components with improved mechanical stability and extended lifespan.
Implementation Method 1
deposition of an aluminium-containing nitride nucleation layer on the silicon surface of the substrate
Implementation Method 2
deposition of a masking layer on the nitride nucleation layer or, where present, on the first nitride buffer layer
Implementation Method 3
deposition of a gallium-containing first nitride semiconductor layer on the masking layer
Data Source
AI summary
A process for the production of a layer structure of a nitride semiconductor component on a silicon surface, comprising: provision of a substrate having a silicon surface; deposition of an aluminium-containing nitride nucleation layer on the silicon surface of the substrate; optional: deposition of an aluminium-containing nitride buffer layer on the nitride nucleation layer; deposition of a masking layer on the nitride nucleation layer or, if present, on the first nitride buffer layer; deposition of a gallium-containing first nitride semiconductor layer on the masking layer, wherein the masking layer is deposited in such a way that, in the deposition step of the first nitride semiconductor layer, initially separate crystallites grow that coalesce above a coalescence layer thickness and occupy an average surface area of at least 0.16 μm2 in a layer plane of the coalesced nitride semiconductor layer that is perpendicular to the growth direction.