Semiconductor Device With Varying Dopant Concentrations
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Solution Overview
Problem
Conventional semiconductor devices with uniform dopant distribution in drift regions often suffer from high 'on' resistance and reduced withstand voltage due to distortion of the depletion layer, leading to easy breakdown.
Innovation Solution
A semiconductor device structure with a first and second semiconductor layer, where the second layer is lightly doped relative to the first, featuring column regions with sub-column regions having varying doping concentrations, formed using a thermal driver and injection of dopants at an inclination angle to create a smooth depletion layer and enhance withstand voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If uniform dopant distribution is used in drift regions, then manufacturing is simple, but on-resistance is high and withstand voltage is reduced
Solution Approach 1:
The patent applies local quality by creating non-uniform dopant distribution in the drift region through columnar structures with varying doping concentrations. The drift region contains column regions with sub-column regions having different dopant concentrations, where the doping concentration varies laterally to optimize both electrical performance and manufacturing feasibility. This local variation in dopant concentration improves withstand voltage while maintaining reasonable manufacturing complexity.
2Device complexity
If uniform dopant distribution is used in drift regions, then device structure is simple, but depletion layer distortion occurs leading to easy breakdown
Solution Approach 1:
The patent implements local quality by introducing columnar structures with spatially varying dopant concentrations in the drift region. These column regions contain sub-column regions with different doping levels, creating local variations that prevent depletion layer distortion and improve breakdown resistance while adding controlled structural complexity.
Solution Approach 2:
The patent applies segmentation by dividing the drift region into multiple column regions, each containing sub-column regions with distinct dopant concentrations. This segmentation of the uniform drift region into structured zones allows for optimized electrical field distribution and improved reliability against breakdown.
3Reliability
If dopants are injected at inclination angle with thermal driver, then withstand voltage increases due to smooth depletion layer, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies parameter changes by utilizing thermal driver conditions to control dopant diffusion during injection at inclination angles. By adjusting thermal parameters (temperature, time) and injection parameters (angle, concentration), the process achieves smooth depletion layer formation and improved withstand voltage while managing the increased manufacturing precision requirements through controlled parameter variations.
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 results in a semiconductor device with reduced 'on' resistance and increased withstand voltage, preventing easy breakdown while maintaining low resistance.
Implementation Method 1
forming a second column region using a thermal driver and by injecting the dopants of the first type into an opening between two of the first column regions
Data Source
AI summary
A semiconductor device structure can include: (i) a first semiconductor layer having dopants of a first type; (ii) a second semiconductor layer having the dopants of the first type on the first semiconductor layer, where the second semiconductor layer is lightly-doped relative to the first semiconductor layer; (iii) first and second column regions spaced from each other in the second semiconductor layer, where the second column region is arranged between two of the first column regions; and (iv) first and second first sub-column regions laterally arranged in the second column region, where a doping concentration of the first sub-column region decreases in a direction from the first column region to the second sub-column region, and where a doping concentration of the second sub-column region decreases in a direction from the first column region to the first sub-column region.