SiC Epitaxial Growth Using Sublimation for Doping Control
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Solution Overview
Problem
The chemical vapor deposition method for manufacturing SiC epitaxial substrates faces challenges in controlling the growth environment due to the mixing of source, carrier, and dopant gases, necessitating optimization of multiple parameters such as gas flow rates and heating temperatures.
Innovation Solution
A method involving the use of a SiC substrate and a SiC material with a lower doping concentration, arranged to face each other, to transport a raw material and form a SiC epitaxial layer, with a temperature gradient and controlled heating to reduce parameters and control doping concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If chemical vapor deposition method is used to form SiC epitaxial layer, then SiC epitaxial layer can be formed on SiC single crystal substrate, but it is difficult to control the growth environment due to mixing of source gas, carrier gas, and dopant gas
Solution Approach 1:
The invention extracts and eliminates the carrier gas from the chemical vapor deposition process. By using solid SiC material as the carbon source instead of gaseous precursors requiring carrier gas, the system removes the complexity of mixing and controlling multiple gases (source gas, carrier gas, dopant gas), thereby improving growth environment control while maintaining epitaxial layer formation capability
Solution Approach 2:
The invention changes the physical state parameter of the carbon source from gaseous (requiring carrier gas) to solid (SiC material). This parameter change eliminates the need for carrier gas and simplifies the gas phase composition, allowing better control of the growth environment by reducing the number of parameters to optimize
2Ease of manufacture
If multiple gases are mixed in chemical vapor deposition, then source gas, carrier gas, and dopant gas can be supplied, but multiple parameters such as flow rate of each gas and heating temperature must be optimized
Solution Approach 1:
The invention extracts the carrier gas component from the gas supply system and replaces it with solid SiC material. This eliminates the need to control and optimize carrier gas flow rate, reducing the number of parameters to be optimized from multiple gas flow rates and temperature to a simpler system with fewer control variables
Solution Approach 2:
The solid SiC material serves as a self-contained carbon source that sublimates directly without requiring carrier gas transport. This self-service approach eliminates the interdependence between carrier gas flow and carbon source delivery, simplifying the parameter optimization process
3Productivity
If conventional chemical vapor deposition is used, then SiC epitaxial layer can be formed, but high-speed growth suitable for withstand voltage layers is limited
Solution Approach 1:
The invention changes the carbon source from gaseous precursors to solid SiC material, enabling higher growth temperatures and faster growth rates. The direct sublimation of solid SiC provides a stable carbon supply that supports high-speed epitaxial growth while maintaining precise doping concentration control through the doping concentration of the SiC material itself
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 allows for the formation of a SiC epitaxial layer with controlled doping concentration and reduced basal plane dislocation density, enabling high-speed growth suitable for withstand voltage layers in semiconductor devices.
Implementation Method 1
a source gas is thermally decomposed in a carrier gas, and silicon (Si) atoms and carbon (C) atoms are continuously deposited
Implementation Method 2
transporting a raw material from the SiC material to the SiC substrate
Implementation Method 3
heating is performed so as to form a raw material transport space having a temperature gradient between the SiC substrate and the SiC material
Data Source
AI summary
The present invention addresses the problem of providing a novel SiC epitaxial substrate manufacturing method and manufacturing device therefor. An SiC substrate and an SiC material, which has a lower doping concentration than said SiC substrate, are heated facing one another, and material is transported from the SiC material to the SiC substrate to form an SiC epitaxial layer. As a result, in comparison with the existing method (chemical vapour deposition), it is possible to provide an SiC epitaxial substrate manufacturing method with a reduced number of parameters to be controlled.