Semiconductor Device Asymmetric Well Doping for IGBT Performance
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Solution Overview
Problem
Current semiconductor devices with insulated gate bipolar transistors (IGBTs) face challenges in maintaining or improving driving current and on-state resistance as they shrink in size, limiting further electrical performance enhancement.
Innovation Solution
The semiconductor device incorporates a semiconductor layer with specific doped regions and gate structures, including asymmetric cross-sectional profiles and additional MOS devices, formed using a semiconductor-on-insulator substrate and deep trench isolation to enhance electrical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the device size is reduced, then the integration density increases, but the driving current decreases and on-state resistance increases
Solution Approach 1:
The patent applies asymmetry by forming a doped well region with an asymmetric cross-sectional profile, where the depth varies across the region. This asymmetric doping profile optimizes the electrical characteristics to maintain driving current and on-state resistance performance even as device dimensions are reduced for higher integration density.
Solution Approach 2:
The patent implements local quality by creating regions with different doping types and concentrations within the semiconductor structure. Specifically, a doped well region with asymmetric profile is formed in specific locations to locally optimize electrical properties, allowing different parts of the device to have tailored characteristics that maintain performance during size reduction.
2Reliability
If additional doped regions and gate structures are added, then electrical performance improves, but device complexity increases
Solution Approach 1:
The patent merges multiple functions into integrated structures. The doped well region with asymmetric profile serves multiple purposes: it controls threshold voltage, modulates doping concentration, and optimizes electrical characteristics. This consolidation of functions into a single asymmetrically-doped region improves electrical performance while avoiding the need for multiple separate complex structures.
Solution Approach 2:
The patent utilizes parameter changes by varying the doping concentration and depth profile across the doped well region. The asymmetric cross-sectional profile creates a gradient in doping parameters that optimizes electrical performance. By controlling doping parameters (concentration, depth, distribution) rather than adding more structures, the patent achieves improved electrical characteristics with controlled 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 configuration improves driving currents and reduces on-state resistance, maintaining or enhancing electrical performance while preventing latch-up effects and noise, even as the device size reduces.
Implementation Method 1
A thermal diffusion process is performed to diffuse the dopants of the first conductivity type of the first doped region into the second doped well region adjacent thereto
Data Source
AI summary
A semiconductor device includes: a semiconductor layer; a first doped well region disposed in a portion of the semiconductor layer; a first doped region disposed in the first doped well region; a second doped well region of an asymmetrical cross-sectional profile disposed in another portion of the semiconductor layer; second, third, and fourth doped regions formed in the second doped well region; a first gate structure disposed over a portion of the semiconductor layer, practically covering the second doped well region; and a second gate structure embedded in a portion of the semiconductor layer, penetrating a portion of the second doped well region.