MOSFET Body Contact Implant Layout for Lower Ron·A
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Solution Overview
Problem
Existing silicon power MOSFET manufacturing methods face challenges in reducing the on-state resistance (Ron) multiplied by area (A) without compromising electrical performance and robustness, particularly during breakdown phenomena.
Innovation Solution
The proposed solution involves a semiconductor device with a semiconductor body having P-type doping, featuring source regions with N+ type implants and body contact regions with P+ type implants. The body contact regions are designed with a tapered shape along the Y-axis direction, optimizing the ratio of N+ to P+ regions to minimize facing surface area towards the gate regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the distance between gate regions is reduced to improve area utilization, then the Ron·A parameter improves, but the manufacturing precision deteriorates due to photolithographic and implant resolution limits
Solution Approach 1:
The body contact region is segmented into multiple discrete body contact sub-regions arranged along the Y-axis, rather than forming a continuous stripe. This segmentation allows the distance de between gate regions to be reduced while maintaining manufacturability, as each sub-region can be independently formed with standard photolithographic and implant resolution
Solution Approach 2:
The body contact region transitions from a two-dimensional continuous stripe (extending along Y-axis) to a set of discrete sub-regions distributed along the Y-axis direction. This dimensional reorganization allows better packing density and reduced gate spacing while maintaining the electrical function of body contact
2Reliability
If the body contact region is made continuous to improve electrical contact, then the reliability improves, but the area occupied increases reducing productivity
Solution Approach 1:
The continuous body contact stripe is divided into multiple discrete body contact sub-regions that are distributed along the Y-axis. These segmented sub-regions maintain adequate electrical contact reliability by providing multiple contact points, while simultaneously improving area efficiency by reducing the total occupied area compared to a continuous stripe
Solution Approach 2:
Different regions of the device are treated with different body contact configurations: discrete sub-regions in areas where area efficiency is critical, potentially allowing continuous or denser configurations where electrical contact reliability is the primary concern. This local differentiation optimizes both reliability and area utilization
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 effectively reduces the Ron·A parameter while maintaining robustness, as evidenced by the optimized ratio of source to body contact region areas, which enhances electrical performance without degrading breakdown voltage withstand.
Implementation Method 1
formed by a P+ type implant in the semiconductor body 10
Implementation Method 2
formed by N+ type implants in the semiconductor body 10
Data Source
AI summary
Electronic device, comprising: a semiconductor body having a surface, an electrical conductivity P and a first doping value; at least one gate region on the surface; one or more source regions, having a second electrical conductivity N, extending in the semiconductor body at the surface and at a first side of the gate region; and at least one body contact region, of P+ type, extending in the semiconductor body at the surface and at the first side of the gate region 22. The first gate region has the shape of a stripe with main extension along a first direction. The first body contact region has a tapered shape along said first direction. The one or more source regions are adjacent to, and at least partially surround, the first body contact region.