Semiconductor Conductive Layer Width Variation for Current Crowding
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Solution Overview
Problem
Ultra-high voltage semiconductor devices experience current crowding at the source terminal, leading to reduced breakdown voltage and high leakage current due to the current crowding effect.
Innovation Solution
A semiconductor device design with a conductive layer that varies in width according to the border curvature of the source region, with a greater width at more curved areas to dissipate high electric fields, and includes a substrate with specific conductivity types and well regions to enhance breakdown voltage and reduce leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional ultra-high voltage device structure is used, then the device can operate at high voltage, but current crowding effect occurs at the source terminal leading to reduced breakdown voltage and high leakage current
Solution Approach 1:
The conductive layer is designed with non-uniform width where the width at the source region (first width) is greater than the width at the drain region (second width). This local variation in conductive layer geometry creates non-uniform electric field distribution that specifically addresses the current crowding problem at the source terminal while maintaining overall device functionality
Solution Approach 2:
The conductive layer exhibits asymmetric geometry relative to the source and drain regions, with the wider portion positioned at the source region and the narrower portion at the drain region. This asymmetric configuration is specifically designed to counteract the symmetric current crowding effect that occurs at the source terminal in conventional devices
2Reliability
If the conductive layer has uniform width, then the device structure is simple, but the electric field is not uniformly distributed causing high leakage current
Solution Approach 1:
The conductive layer width is locally varied to create different electrical characteristics at different regions. The wider section at the source region provides enhanced charge distribution and field control, while the narrower section at the drain region maintains appropriate electrical properties for that region, achieving uniform electric field distribution without requiring complete structural redesign
Solution Approach 2:
The geometric parameter of the conductive layer (width) is changed across different regions of the device. By varying the width parameter from the source region to the drain region, the electric field distribution is optimized to reduce leakage current while maintaining a relatively simple single-layer conductive structure
Data Source
AI summary
Provided is a semiconductor device including a substrate, an isolation structure, a gate structure, source and drain regions and a conductive layer. The source and drain regions are disposed in the substrate. The isolation structure is disposed between the source and drain regions. The gate structure is disposed on the substrate between the source and drain regions. The conductive layer is disposed on the substrate, extends from above the source region to above the isolation structure and is electrically connected to the source region. The substrate has first and second areas. The source region in the second area has a border curvature greater than that in the first area. The width of the portion of the conductive layer covering the isolation structure in the second area has a width greater than that in the first area.