Trench Conductive Member Isolation for Higher Breakdown Voltage
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Solution Overview
Problem
Existing semiconductor devices face challenges in maintaining reliable operation due to the risk of electrical breakdown, particularly with thick insulation layers required to prevent breakdown, which increase device size and complexity.
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, thereby 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, then reliability is improved, but device size increases
Solution Approach 1:
The insulation system is divided into two segments: a first insulating layer lining the trench wall and a second insulating layer on top. This segmentation allows each layer to be optimized for different functions - the first layer provides field control and prevents breakdown at the critical trench interface, while the second layer provides additional insulation thickness without increasing lateral device size
Solution Approach 2:
The patent transitions from a planar insulation approach to a three-dimensional trench-based insulation structure. By extending insulation vertically into the substrate through trenches, the design achieves higher breakdown voltage through increased effective insulation path length without proportionally increasing the device's planar footprint
2Reliability
If a thick insulation layer is used to prevent electrical breakdown, then reliability is improved, but device complexity increases
Solution Approach 1:
The insulation structure is segmented into functionally distinct layers - a first insulating layer for field control at the trench interface and a second insulating layer for additional breakdown protection. This segmentation allows each layer to be optimized independently while maintaining overall structural simplicity
Solution Approach 2:
The trench structure serves multiple functions simultaneously: it provides mechanical support, establishes electrical field control through the first insulating layer, and enables enhanced breakdown voltage through the second insulating layer. This multi-functionality reduces the need for separate dedicated structures for each function
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, reducing the risk of electrical breakdown while minimizing device size and complexity.
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
AI summary
In an exemplary embodiment, a semiconductor device includes 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.