Trenched-Gate Transistor Termination via Variable Spacing
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Solution Overview
Problem
The formation of traditional termination structures for trenched-gate power transistors requires additional processing steps and masking, increasing production costs and may not be compatible with certain trenched-gate power transistors, while also resulting in varying breakdown voltages across different regions of the array.
Innovation Solution
The solution involves designing trenched-gate semiconductor devices with outer transistors having a greater average termination region spacing than inner transistors, allowing for enhanced breakdown voltage without the need for additional processing steps, by spacing trenches in a manner that increases breakdown voltage in the termination region relative to the inner region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional termination structures are formed in the termination region, then breakdown voltage uniformity is improved, but device complexity and manufacturing cost increase due to additional processing steps and masking
Solution Approach 1:
The patent changes the physical parameters of the trench gates in the termination region by increasing the spacing between adjacent trench gates compared to the inner region. This parameter change (greater spacing) directly increases the breakdown voltage in the termination region, achieving breakdown voltage uniformity across the device without requiring additional termination structures or processing steps
Solution Approach 2:
The patent applies local quality by creating different trench gate spacing configurations in different regions of the device. The inner region has a first spacing between adjacent trench gates, while the termination region has a second spacing that is greater than the first spacing. This localized variation in spacing optimizes the breakdown voltage characteristics for each specific region's functional requirements
2Reliability
If traditional termination structures are formed in the termination region, then breakdown voltage uniformity is improved, but production cost increases due to additional processing steps and masking
Solution Approach 1:
The patent changes the physical parameters of the trench gates in the termination region by increasing the spacing between adjacent trench gates compared to the inner region. This parameter change (greater spacing) directly increases the breakdown voltage in the termination region, achieving breakdown voltage uniformity across the device without requiring additional termination structures or processing steps
Solution Approach 2:
The patent makes the trench gate spacing configuration serve multiple functions: it defines the active transistor regions in the inner area while simultaneously providing the termination function in the outer region. This eliminates the need for separate termination structures, reducing manufacturing complexity and cost while achieving both transistor functionality and breakdown voltage uniformity
3Ease of manufacture
If uniform trench spacing is used across the entire array, then manufacturing simplicity is maintained, but breakdown voltage varies across different regions
Solution Approach 1:
The patent applies local quality by creating different trench gate spacing configurations in different regions of the device. The inner region has a first spacing between adjacent trench gates, while the termination region has a second spacing that is greater than the first spacing. This localized variation in spacing optimizes the breakdown voltage characteristics for each specific region's functional requirements
Data Source
AI summary
Power device termination structures and methods are disclosed herein. The structures include a trenched-gate semiconductor device. The trenched-gate semiconductor device includes a semiconducting material and an array of trenched-gate power transistors. The array defines an inner region including a plurality of inner transistors and an outer region including a plurality of outer transistors. The inner transistors include a plurality of inner trenches that has an average inner region spacing. The outer transistors include a plurality of outer trenches that has an average termination region spacing. The average termination region spacing is greater than the average inner region spacing or is selected such that a breakdown voltage of the plurality of outer transistors is greater than a breakdown voltage of the plurality of inner transistors.