Semiconductor Drift Region Design for Breakdown Voltage
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Solution Overview
Problem
The challenge is to increase the breakdown voltage of semiconductor devices while minimizing transistor size and on-resistance, as efforts to decrease transistor size lower the breakdown voltage, reducing the margin between the rated and breakdown voltages, and making it difficult to accommodate manufacturing variations and transient voltage fluctuations.
Innovation Solution
The solution involves a semiconductor device structure that combines a buried lateral drift region with vertical drift regions to distribute drain voltage both vertically and laterally, enhancing the breakdown voltage by providing conductive paths for current and effectively dissipating drain voltage, thereby increasing the margin between rated and breakdown voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If transistor size is decreased to minimize device area, then area is reduced, but breakdown voltage decreases
Solution Approach 1:
The patent introduces a buried lateral drift region that extends horizontally beneath the channel, adding a lateral dimension to the traditional vertical drift structure. This lateral extension allows the electric field to be distributed over a larger volume without increasing the device footprint, thereby maintaining small area while achieving higher breakdown voltage through three-dimensional field management
Solution Approach 2:
The drift region is segmented into a buried lateral portion and a vertical portion, creating distinct functional zones. The buried lateral drift region handles horizontal field distribution while the vertical drift region manages vertical field components, allowing each segment to be optimized independently for its specific electric field direction, thus achieving high breakdown voltage in a compact structure
2Area of moving object
If transistor size is decreased to minimize device area, then area is reduced, but on-resistance increases
Solution Approach 1:
By extending the drift region laterally beneath the channel, the patent creates an additional conduction path dimension. This lateral extension provides parallel current paths that reduce the effective resistance without requiring a larger device area, as the current可以利用 the extended lateral region to flow more efficiently
Solution Approach 2:
The buried lateral drift region is nested beneath the channel structure, utilizing the space under the existing transistor components. This nested configuration adds functional drift region volume without occupying additional lateral space, effectively reducing on-resistance while maintaining compact device dimensions
Data Source
AI summary
Semiconductor device structures and related fabrication methods are provided. An exemplary semiconductor device structure includes a first vertical drift region of semiconductor material, a second vertical drift region of semiconductor material, and a buried lateral drift region of semiconductor material that abuts the vertical drift regions. In one or more embodiments, the vertical drift regions and buried lateral drift region have the same conductivity type, wherein a body region of the opposite conductivity type overlies the buried lateral drift region between the vertical drift regions.