Vertical SiC Epitaxial Reactor for Uniform Batch Wafer Growth
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Solution Overview
Problem
The high cost and low throughput of existing silicon carbide epitaxial reactors, coupled with the complexity and high defectivity of silicon carbide substrates, hinder the widespread adoption of silicon carbide-based semiconductor devices, particularly for high-power applications.
Innovation Solution
A modular, high-throughput vertical epitaxial reactor design that allows simultaneous processing of multiple silicon carbide wafers using a batch mode process, incorporating removable vertical susceptors with tilted wafer holders and a counterflow gas exchange system to enhance uniformity and efficiency, reducing energy consumption and maintenance costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If single wafer SiC epitaxial reactors are used, then manufacturing precision is maintained, but productivity is low and capital cost is high
Solution Approach 1:
The reactor is divided into multiple independent susceptor positions (at least two) that can process multiple wafers simultaneously. Each susceptor holds wafers in a vertical orientation, allowing parallel processing while maintaining individual process control for each position, thus increasing throughput without compromising epitaxial layer quality.
Solution Approach 2:
The patent transitions from horizontal wafer processing to vertical wafer orientation. Wafers are held vertically on susceptors, changing the dimensional arrangement from horizontal layers to vertical stacks. This enables multiple wafers to be processed in the same reaction zone simultaneously, dramatically increasing productivity while maintaining process precision.
2Productivity
If batch type SiC epitaxial reactors are used, then productivity increases, but capital cost increases substantially with only minimal throughput improvement
Solution Approach 1:
The reactor design uses universal susceptors that can hold multiple wafers in vertical orientation and are compatible with standard epitaxial processing. The same reaction chamber and gas delivery system serve all susceptor positions, allowing the system to process multiple wafers without requiring separate processing lines, thus improving throughput without proportionally increasing capital cost.
Solution Approach 2:
The vertical susceptor design allows wafers to be self-supported through their own structural integrity, eliminating the need for complex mechanical holding mechanisms. The wafers are simply placed vertically on the susceptor and held in place by their own rigidity, simplifying the reactor design while enabling batch processing of multiple wafers simultaneously.
3Productivity
If multiple wafers are processed simultaneously, then productivity increases, but manufacturing precision and defectivity control become more difficult
Solution Approach 1:
Each susceptor position is designed to provide localized process conditions optimized for vertical wafer processing. The gas flow, temperature distribution, and reactant delivery are tailored to the vertical orientation and specific position within the reactor, ensuring that each wafer receives appropriate process conditions for high-quality epitaxial growth even when multiple wafers are processed simultaneously.
Solution Approach 2:
The patent optimizes process parameters specifically for vertical wafer processing, including gas flow rates, temperature profiles, and reactant concentrations. These parameter changes are tailored to the vertical orientation and batch configuration, enabling precise control of epitaxial growth conditions across multiple wafers simultaneously, thus maintaining manufacturing precision while increasing throughput.
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 solution achieves lower processing costs, improved device performance, and higher yield by ensuring uniform epitaxial layer growth with reduced defectivity, thereby enabling cost-effective production of high-power silicon carbide devices.
Implementation Method 1
modular silicon carbide epitaxial reactor comprises inlet gas manifold configured for delivering process gases required for growing one or more silicon carbide layers on two or more silicon carbide wafers per module
Implementation Method 2
inlet heat exchanger having plurality of inputs and plurality of outputs configured to heat process gases to predetermined temperature
Implementation Method 3
where a surface of each silicon carbide wafer is tilted relative to vertical to compensate for depletion of reactants
Data Source
AI summary
A batch mode SiC (Silicon Carbide) epitaxial reactor comprising an inlet gas manifold, an inlet heat exchanger coupled to the inlet gas manifold, a plurality of removable vertical susceptors configured to couple to the inlet heat exchanger, a plurality of exhaust heat exchangers coupled to the plurality of removable vertical susceptors, and a scrubber coupled to the plurality of exhaust heat exchangers. Each removable vertical susceptor is configured to hold at least two SiC wafers tilted in a vertical fixed position relative to a flow of heated gases output by the inlet heat exchanger. The plurality of exhaust heat exchangers are configured to heat hydrogen gas. The heated hydrogen gas is configured to couple to the inlet heat exchanger to heat gases provided through the inlet gas manifold to grow SiC on the plurality of SiC wafers in the plurality of removable vertical susceptors thereby reducing energy consumption.