Buried Gate Electrode with Dual Gate Contacts
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Solution Overview
Problem
Conventional semiconductor devices with buried gate electrodes face challenges in providing reliable and cost-effective gate contacts, particularly in maintaining reverse blocking capabilities while reducing on-state resistance, and in avoiding damage to the second field dielectric during the etching process for gate contacts.
Innovation Solution
The semiconductor device incorporates a dual gate contact structure with a first and second gate portion on opposite sides of a longitudinal center axis, allowing for deep and reliable gate contacts to be formed without sophisticated etch endpoint detection, ensuring a contiguous barrier layer and minimizing damage to the second field dielectric.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single gate contact is provided in the center of the gate electrode, then the manufacturing process is simpler, but the contact may damage the second field dielectric and the gate contact reliability is reduced
Solution Approach 1:
The gate electrode is divided into two separate gate portions (first gate portion and second gate portion) on opposite sides of the longitudinal center axis. Correspondingly, gate contacts are provided separately for each gate portion instead of a single central contact. This segmentation allows each contact to be positioned optimally without damaging the second field dielectric, thereby improving reliability while maintaining manufacturing simplicity.
2Reliability
If gate contacts are extended deep into the semiconductor portion, then contact reliability improves, but the risk of damaging the second field dielectric increases
Solution Approach 1:
Instead of providing a single deep central contact that risks damaging the second field dielectric, the invention distributes contacts laterally across two gate portions. This dimensional redistribution allows contacts to reach adequate depths for reliability while maintaining safe lateral distances from the second field dielectric, thus avoiding damage.
3Ease of manufacture
If the gate electrode structure is simplified, then manufacturing cost decreases, but the ability to maintain reverse blocking capabilities while reducing on-state resistance is compromised
Solution Approach 1:
The gate electrode structure employs different configurations for different regions: the first and second gate portions are positioned to enable deep contacts for low on-state resistance, while the third gate portion (central region) is designed to maintain reverse blocking capabilities. This local differentiation allows each region to optimize its function without compromising overall device performance.
Data Source
AI summary
A semiconductor device includes a gate electrode buried in a semiconductor portion. The gate electrode includes a first gate portion on a first side of a longitudinal center axis of the gate electrode parallel to the main surface and a second gate portion on an opposite, second side of the longitudinal center axis. At least one first gate contact extends from a main side defined by a main surface into the first gate portion.