Nitrogen Boron Doped SiC Body Resistivity Control
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Solution Overview
Problem
CVD-SiC formed bodies used in semiconductor production processes require low light transmittance and high resistivity, but existing methods struggle to achieve these properties simultaneously, particularly for applications like etchers where high resistivity (e.g., 10 Ω·cm or more) is needed.
Innovation Solution
A nitrogen and boron-doped SiC body is formed using a CVD method with specific concentrations of boron (1 to 30 mass ppm) and nitrogen (100 to 1000 mass ppm) atoms, and a method involving a feed gas, boron compound gas, nitrogen-containing compound gas, and carrier gas is introduced into a reaction chamber to achieve the desired properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a CVD-SiC formed body is produced using conventional CVD methods, then the material exhibits high density and high purity, but the resistivity is too low and light transmittance is too high for etcher applications
Solution Approach 1:
The patent applies parameter changes by precisely controlling the concentrations of boron (1-30 mass ppm) and nitrogen (100-1000 mass ppm) atoms in the CVD-SiC formed body. By adjusting these dopant parameters during the CVD process, the resistivity is controlled to be 10 Ω·cm or more while maintaining high density and purity, resolving the contradiction between material reliability and resistivity control.
2Illumination intensity
If nitrogen gas is added during CVD to reduce light transmittance, then light transmittance decreases, but resistivity also decreases making it unsuitable for etchers
Solution Approach 1:
The patent employs composite doping with both boron and nitrogen atoms to create a CVD-SiC formed body with composite properties. The boron doping provides high resistivity (10 Ω·cm or more) while nitrogen doping reduces light transmittance to 5% or less. This composite approach allows simultaneous achievement of low light transmittance and high resistivity, making the material suitable for etcher applications.
3Manufacturing precision
If boron doping is increased to raise resistivity, then resistivity improves, but light transmittance increases which is unacceptable for etchers
Solution Approach 1:
The patent applies local quality by assigning different functional roles to different dopant elements within the same material. Boron atoms (1-30 mass ppm) are introduced specifically to control resistivity to 10 Ω·cm or more, while nitrogen atoms (100-1000 mass ppm) are introduced specifically to control light transmittance to 5% or less. This differentiated doping strategy allows each element to optimize a specific property without compromising the other.
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 resulting CVD-SiC formed body exhibits low light transmittance and high resistivity, making it suitable for semiconductor production processes, such as etchers, with resistivity ranging from 10 Ω·cm to 100,000 Ω·cm and light transmittance of 0 to 1% at 950 nm.
Implementation Method 1
a CVD-SiC formed body that is obtained by depositing SiC on the surface of a substrate using a chemical vapor deposition (CVD) method
Data Source
AI summary
A CVD-SiC formed body has low light transmittance and high resistivity, and may suitably be used as a member for an etcher that is used for a semiconductor production process, for example. The SiC formed body is formed using a CVD method, and includes 1 to 30 mass ppm of boron atoms, and more than 100 mass ppm and 1000 mass ppm or less of nitrogen atoms. The SiC formed body preferably has a resistivity of more than 10 Ω·cm and 100,000 Ω·cm or less, and a light transmittance at a wavelength of 950 nm of 0 to 1%.