Trench Conductive Member Cavity Insulation for Higher Breakdown Voltage
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Solution Overview
Problem
Existing semiconductor devices face challenges in reducing the risk of electrical breakdown while maintaining reliable insulation and minimizing device size, as thick insulation layers required for high voltages occupy more space.
Innovation Solution
A semiconductor device design featuring a conductive member in a trench with an enclosed cavity and a lower isolating member, where the peripheral edge of the conductive member is exposed within the cavity, providing improved electrical insulation and mechanical support, thus enhancing breakdown voltage and electromechanical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thick insulation layer is used to prevent electrical breakdown at high voltages, then the breakdown voltage is improved, but the device size increases
Solution Approach 1:
The insulation system is divided into two distinct components: a lower isolating member (solid insulation layer) and an enclosed cavity (void space). This segmentation allows the conductive member to be insulated from the substrate through a combination of solid insulation and air gap, achieving high breakdown voltage while minimizing the total vertical space required compared to a single thick insulation layer
Solution Approach 2:
The enclosed cavity acts as an intermediary element between the conductive member and the substrate. This air gap provides additional electrical insulation with minimal space requirement, complementing the lower isolating member to achieve the required breakdown voltage without proportionally increasing device size
2Volume of moving object
If the conductive member is closely spaced to the trench base to minimize device size, then the device size is reduced, but the risk of electrical breakdown increases
Solution Approach 1:
The insulation function is segmented between the lower isolating member and the enclosed cavity, allowing the conductive member to be positioned closer to the trench base while maintaining adequate insulation distance through the combination of solid insulation and air gap
Solution Approach 2:
The lower isolating member is positioned specifically at the base of the trench where electrical insulation is most critical, providing localized insulation enhancement exactly where the conductive member interfaces with the substrate region, thereby preventing breakdown without requiring uniform thick insulation throughout
3Reliability
If a thick insulation layer is used to ensure reliable insulation, then the electrical insulation is improved, but the manufacturing complexity increases
Solution Approach 1:
The insulation structure is segmented into the lower isolating member and enclosed cavity, which can be formed through standard semiconductor fabrication processes such as selective etching and deposition, avoiding the need for single-step thick insulation formation while maintaining manufacturing feasibility
Solution Approach 2:
The enclosed cavity serves as a simple intermediary structure that can be formed by conventional etching processes, providing insulation functionality without requiring complex multi-layer insulation stacks or specialized manufacturing steps
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 design effectively increases breakdown voltage and improves electromechanical stability by optimizing the relationship between the conductive member and the isolating member, reducing the risk of electrical breakdown while minimizing device size.
Implementation Method 1
The enclosed cavity and the lower electrically isolating member together electrically insulate the electrically conductive member arranged in the trench from the semiconductor substrate
Implementation Method 2
The lower isolating member mechanically supports the lower end of the conductive member within the trench
Data Source
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AI summary
In an exemplary embodiment, a semiconductor device comprises a semiconductor substrate having a first major surface, one or more trenches formed in the first major surface and having a base and a side wall extending from the base to the first major surface and a conductive member arranged in at least one trench of the one or more trenches. The conductive member is spaced apart from the base of the at least one trench by a lower isolating member and from the side wall of the at least one trench by an enclosed cavity located in the at least one trench. The conductive member has a lower face. A peripheral edge of the lower face of the conductive member is located in the cavity and a central portion of the lower face is in contact with the lower isolating member.