Trench Semiconductor Contact Layout for Lower On-Resistance
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Solution Overview
Problem
Conventional semiconductor devices with trench gate structures face increased contact resistance and on-resistance due to the limited connection area between the contact region and the electrode, especially when the contact region's length is reduced.
Innovation Solution
The semiconductor device incorporates a trench gate structure with alternating impurity regions of higher concentration, featuring acute angles in the contact sides of the impurity regions to increase the contact area without extending the impurity region length, thereby reducing on-resistance and contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the contact region length is reduced, then the device area is decreased, but the contact resistance and on-resistance increase
Solution Approach 1:
The contact region is designed with an asymmetric shape where the width varies along its length. The contact region has a first width at one end and a second width at the other end, with the widths being different. This asymmetric configuration allows the contact region to maintain a larger effective contact area with the electrode while occupying less overall device area, thereby reducing both contact resistance and on-resistance without increasing the device footprint.
Solution Approach 2:
The invention transitions from a conventional rectangular contact region to a trapezoidal or triangular shape, utilizing the width dimension variation along the length. By introducing a width dimension that changes along the length of the contact region, the design achieves larger contact area perpendicular to the current flow direction while maintaining compact device area, effectively resolving the contradiction between device area and contact resistance.
2Area of moving object
If the contact region length is reduced, then the device area is decreased, but the on-resistance increases
Solution Approach 1:
The asymmetric contact region design with varying width along its length increases the effective cross-sectional area for current flow. The contact region has a first width at one end and a second width at the other end, creating a larger average width that reduces on-resistance. This allows the device to maintain lower on-resistance with a shorter contact region length, thereby reducing overall device area.
Solution Approach 2:
The invention changes the geometric parameters of the contact region, specifically the width parameter, which varies along the length of the contact region. By making the width a variable parameter rather than a constant, the design achieves optimized current distribution and reduced on-resistance while maintaining compact dimensions.
Data Source
AI summary
A first impurity region and a second impurity region are alternately formed along a longitudinal direction of a first trench. The second impurity region has: a first contact side in contact with the first trench; and a second contact side in contact with a second trench adjacent to the first trench. A first linear portion is defined to extend from a boundary of the first contact side toward the second trench, and a second linear portion is defined to extend from a boundary of the second contact side toward the first trench. A first angle between the first trench and the first linear portion connected to the first contact side is less than 90° and a second angle between the second trench and the second linear portion connected to the second contact side is less than 90° .