Semiconductor Donor Layer Doping Profile for High Breakdown Voltage
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Solution Overview
Problem
Existing semiconductor devices with n-type field stop layers face challenges in increasing donor generation rate and improving electrical characteristics, as they require precise control of hydrogen, oxygen, and crystal defects, which current methods fail to adequately address.
Innovation Solution
A semiconductor device and method involving a donor layer with a specific doping concentration profile, including multiple peaks and regions, formed through proton implantation and heat treatment, which generates crystal defects and controls carrier concentration to enhance donor generation rate and electrical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If proton implantation is performed to form donor layer, then carrier concentration is controlled, but donor generation rate is insufficient
Solution Approach 1:
Crystal defects are generated in advance through electron beam irradiation or neutron beam irradiation before proton implantation. This preliminary action creates favorable conditions for subsequent donor generation, allowing the proton implantation to be more effective in generating donors at a higher rate.
Solution Approach 2:
Crystal defects serve as intermediaries that facilitate the transformation of protons into donors. The crystal defects created by electron beam or neutron beam irradiation act as catalysts that enhance the donor generation process during proton implantation, enabling more efficient carrier concentration control.
2Productivity
If crystal defects are generated to increase donor generation rate, then donor generation rate improves, but electrical characteristics deteriorate
Solution Approach 1:
Crystal defects are generated locally and selectively in specific regions of the semiconductor substrate through controlled electron beam or neutron beam irradiation. This localized approach ensures that crystal defects are concentrated where needed for donor generation while minimizing their impact on overall electrical characteristics in other regions.
Solution Approach 2:
The type and amount of crystal defects are precisely controlled by adjusting irradiation parameters such as electron beam energy, neutron flux, and irradiation duration. By changing these parameters, the crystal defect distribution is optimized to maximize donor generation rate while maintaining acceptable electrical characteristics.
3Productivity
If multiple irradiation steps are performed, then donor generation rate increases, but manufacturing complexity increases
Solution Approach 1:
The manufacturing process uses periodic irradiation steps with different types of radiation (electron beam followed by neutron beam, or vice versa). This periodic approach allows each irradiation type to contribute differently to crystal defect formation, synergistically enhancing donor generation while maintaining a structured and manageable process sequence.
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 approach increases the donor generation rate and improves electrical characteristics by optimizing the doping concentration profile and crystal defect distribution, resulting in higher breakdown voltage, reduced leakage current, and enhanced switching performance.
Implementation Method 1
a method has been known which performs proton implantation capable of forming a deep range in n− semiconductor substrate 1
Implementation Method 2
a crystal defect forming step of generating crystal defects before or after the proton implantation is performed
Implementation Method 3
a method has been known which generates crystal defects in the n− drift layer using electron beam irradiation and controls a carrier lifetime
Data Source
AI summary
A semiconductor device including: a semiconductor substrate having a first and a second side, and including a donor layer with a doping concentration profile in a depth direction from the first to the second side. The donor layer includes: a first peak, situated at a first distance from the first side of said substrate; a first region adjacent to the first peak and extending in the depth direction from the first peak toward the first side, a second peak in said doping concentration profile, situated at a second distance from the first side of said substrate. Said second distance is less than said first distance and greater than zero; and a second region adjacent to the second peak and extending in the depth direction from the second peak toward the first side of the substrate, which has a doping concentration which is substantially uniform.