Superjunction Trench MOSFET Edge Layout for Breakdown Voltage
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Solution Overview
Problem
Existing vertical insulated gate field effect transistors with a superjunction structure face issues with insufficient breakdown voltage near the terminal end portions due to localized depletion failure.
Innovation Solution
The semiconductor device incorporates an outer peripheral trench gate connected to cell trench gates and outer peripheral column regions that extend across the cell trench gates, ensuring depletion layers extend uniformly around the terminal ends, enhancing breakdown voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If multiple trench gates are arranged between adjacent p-type column regions to increase current paths, then on-resistance is reduced, but breakdown voltage becomes insufficient in the vicinity of terminal end portions due to localized depletion failure
Solution Approach 1:
The device segments the structure into cell portions containing multiple trench gates for low on-resistance, and outer peripheral portions with extended column regions for high breakdown voltage. This spatial segmentation allows each region to optimize for its specific function without compromising the other.
Solution Approach 2:
Different regions are given different structural qualities: the cell portion has multiple trench gates arranged between column regions to minimize on-resistance, while the outer peripheral portion has column regions extended in the trench gate direction to maximize breakdown voltage. Each local area is optimized for its specific requirement.
2Ease of manufacture
If the device structure is simplified to improve manufacturing, then manufacturing precision and reliability may be compromised
Solution Approach 1:
The extended outer peripheral column regions serve multiple functions: they provide the necessary depletion layer extension for high breakdown voltage, maintain structural uniformity across the device, and can be formed using the same manufacturing processes as the inner column regions, thus achieving both manufacturing simplicity and precision.
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 configuration secures a sufficient withstand voltage in the vicinity of the terminal ends, improving the breakdown voltage performance of the semiconductor device.
Implementation Method 1
An outer peripheral column region is formed on a semiconductor substrate of the outer peripheral portion on the cell portion side with respect to the outer peripheral trench gate. The outer peripheral column region is formed so as to be extended across the first cell trench gate and the second cell trench gate in plan view.
Implementation Method 2
This configuration secures a sufficient withstand voltage in the vicinity of the terminal ends, improving the breakdown voltage performance of the semiconductor device.
Data Source
AI summary
A semiconductor device and a method of manufacturing the same capable of ensuring a sufficient breakdown voltage near a terminal end portion of a cell portion are provided. The cell portion includes a first cell column region and a second cell column region adjacent to each other, and a first cell trench gate and a second cell trench gate arranged between the first cell column region and the second cell column region. An outer peripheral portion includes an outer peripheral trench gate connected to an end portion of each of the first cell trench gate and the second cell trench gate, and a first outer peripheral column region arranged on the cell portion side with respect to the outer peripheral trench gate and extended across the first cell trench gate and the second cell trench gate in plan view.