Trench Gate Contact Offset for Semiconductor Reliability
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Solution Overview
Problem
In semiconductor devices with gate electrodes in trench parts, the formation of concave parts can lead to increased contact resistance and electric field concentration, making it difficult to simultaneously reduce contact resistance and improve breakdown voltage near the trench ends.
Innovation Solution
A semiconductor device design featuring a gate electrode with a concave part on its upper end, where the contact is positioned shifted perpendicular to the source-drain direction relative to the centerline, avoiding the concave part and ensuring the contact does not protrude outside the trench, thus reducing contact resistance and electric field concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If a contact is disposed over the concave part of the gate electrode, then the contact area is reduced, but the contact resistance rises
Solution Approach 1:
The contact is intentionally positioned asymmetrically relative to the gate electrode structure. Specifically, the contact is disposed shifted in a first direction perpendicular to the source-drain direction relative to the centerline in the trench part, placing it on the convex side rather than directly over the concave part. This asymmetric positioning ensures adequate contact area while maintaining electrical connection reliability.
2Area of moving object
If a contact is disposed protruding outside the gate electrode, then the contact area is increased, but the electric field concentrates at the lower end
Solution Approach 1:
The invention applies local quality by carefully positioning the contact within specific spatial boundaries. The contact is disposed shifted perpendicular to the source-drain direction relative to the centerline and is configured not to protrude outside the gate electrode in the source-drain direction. This localized positioning strategy increases contact area while preventing electric field concentration that would occur if the contact extended beyond the gate electrode boundaries.
Data Source
AI summary
To satisfy both suppression of rise in contact resistance and improvement of breakdown voltage near the end part of a trench part. The trench part GT is provided between a source offset region and a drain offset region at least in plan view in a semiconductor layer, and is provided in a source-drain direction from the source offset region toward the drain offset region in plan view. A gate insulating film GI covers the side surface and the bottom surface of the trench part GT. A gate electrode is provided in the trench part at least in plan view, and contacts the gate insulating film GI. A contact GC contacts the gate electrode GE. The contact GC is disposed, shifted in a first direction perpendicular to the source-drain direction relative to the centerline in the trench part GT extending in the source-drain direction in plan view, and is provided in the trench part GT in plan view.