Transmutation Doping for Super-Junction Semiconductor Manufacturing
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Solution Overview
Problem
The manufacturing process for super-junction semiconductor devices is complex and costly, primarily due to the use of high-energy ion implantation and repeated epitaxy and grooving processes.
Innovation Solution
A transmutation doping process using high-energy photon beams or neutron beams to form p-type and n-type heavily doped regions within a lightly doped substrate, followed by annealing treatment, simplifies the process and reduces costs by achieving the necessary doping through nuclear reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional ion implantation or grooving and filling processes are used to manufacture super-junction, then doping precision can be achieved, but manufacturing complexity increases and cost rises
Solution Approach 1:
The patent extracts the doping step from the complex sequence of implantation or epitaxy-grooving cycles. By using transmutation doping, the doping function is achieved in a single nuclear reaction step rather than through multiple sequential process steps, thereby simplifying the overall manufacturing flow while maintaining precise doping concentration control through neutron flux management.
Solution Approach 2:
The patent replaces mechanical/chemical doping methods (ion implantation, epitaxial growth) with a nuclear physics-based method (transmutation doping). This substitution eliminates the need for complex mechanical alignment, mask processing, and chemical vapor deposition equipment, replacing them with a neutron irradiation system that achieves doping through nuclear reactions, thereby reducing manufacturing complexity.
2Manufacturing precision
If repeated epitaxy and ion implantation processes are used, then doping precision is maintained, but manufacturing time and cost increase
Solution Approach 1:
The patent performs preliminary preparation of the semiconductor substrate with controlled boron doping before neutron irradiation. This preliminary action sets the stage for the transmutation reaction to occur at predetermined locations and concentrations, allowing the actual doping to be achieved in a single neutron irradiation step rather than through repeated cycles of epitaxy and implantation, thereby reducing manufacturing cycle time while maintaining precision.
Solution Approach 2:
The neutron irradiation process provides continuous doping action throughout the irradiation period, unlike discrete implantation steps that require repeated cycles. The continuous neutron flux ensures uniform doping distribution and activates doping uniformly throughout the target region, achieving precise doping in a single continuous operation rather than through multiple intermittent steps, thus reducing total manufacturing time.
3Manufacturing precision
If deep reactive ion etching and repeated grooving are performed, then junction depth precision is achieved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts the depth control function from the complex etching and growth process sequence. By using transmutation doping with controlled neutron energy and irradiation time, the junction depth is directly controlled through nuclear reaction physics rather than through multiple etching and growth cycles, thereby simplifying the process while maintaining precise depth control.
Solution Approach 2:
The patent changes the fundamental parameter for depth control from mechanical/thermal processes (etching rate, growth rate) to nuclear physics parameters (neutron energy, irradiation time, cross-section). This parameter change allows direct control of junction depth through the nuclear reaction itself, eliminating the need for complex sequential process steps and reducing device complexity.
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 method simplifies the manufacturing process, reduces costs, and allows for precise control of doping concentrations, making it applicable to various semiconductor devices with different withstand voltages, while maintaining uniform doping distribution.
Implementation Method 1
forming a p-type heavily doped region within the lightly doped substrate through a transmutation doping process by taking a first mask with a pattern of the p-type heavily doped region; forming a high-energy photon beam by using a photon source; and forming a p-type heavily doped region within the lightly doped substrate by a nuclear reaction started by particle radiation on the lightly doped substrate by using the high-energy photon beam
Implementation Method 2
forming an n-type heavily doped region within the lightly doped substrate through a transmutation doping process by taking a second mask with a pattern of the n-type heavily doped region; forming a neutron beam by using a neutron source; and forming an n-type heavily doped region within the lightly doped substrate by a nuclear reaction started by particle radiation on the lightly doped substrate by using the neutron beam
Implementation Method 3
performing annealing treatment
Data Source
Figure 1~3
Figure 4~6
AI summary
Provided is a super-junction manufacturing method, comprising: providing a lightly doped substrate (S11); employing a transmutation doping process to form a P-type heavily doped region (S12) or an N-type heavily doped region (S13); and performing annealing treatment (S14); or providing a first-type heavily doped substrate; employing the transmutation doping process to form a second-type heavily doped region; and performing annealing treatment. Thereby, the manufacturing process is simplified, and production costs are reduced.