Trench Bottom Electric Field Reduction in Semiconductor Devices
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Solution Overview
Problem
The formation of an electric field reducing region at the trench bottom portion in semiconductor devices limits current flow due to high resistance, resulting in decreased forward current and reduced withstand voltage.
Innovation Solution
The electric field reducing region is strategically placed only around the corner portions of the trench bottom, allowing current to flow through the center portion, thereby reducing resistance and maintaining high withstand voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an electric field reducing region is formed in the trench bottom portion, then the reverse withstand voltage is improved, but the forward current decreases due to high resistance
Solution Approach 1:
The electric field reducing region is formed selectively only in the corner portions of the trench bottom, not uniformly across the entire bottom. This localized approach reduces the electric field concentration at corners (improving reverse withstand voltage) while leaving the center portion conductive (maintaining forward current). The selective placement resolves the contradiction by applying the electric field reduction function only where needed.
Solution Approach 2:
The trench bottom is divided into different functional zones: corner portions with electric field reducing regions and a center portion without. This segmentation allows different areas to serve different purposes - corners for voltage withstanding and center for current conduction - thereby resolving the contradiction between reverse withstand voltage and forward current.
2Reliability
If the electric field reducing region covers the entire trench bottom, then the electric field is reduced effectively, but the current flow path is blocked
Solution Approach 1:
Instead of uniformly covering the entire trench bottom, the electric field reducing region is applied locally only to corner portions. This resolves the contradiction by providing electric field reduction exactly where it is needed (at corners where field concentration occurs) while preserving current flow paths in the center region.
Solution Approach 2:
The trench bottom is segmented into corner regions (with electric field reducing regions) and center region (without). This segmentation strategy ensures that the harmful electric field concentration is addressed locally at corners while the center region remains open for current flow, resolving the contradiction between electric field reduction and current flow.
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 suppresses the decrease in forward current while enhancing the reverse withstand voltage by ensuring that the current flows through lower resistance regions, improving the overall performance of the semiconductor device.
Implementation Method 1
a method of reducing an electric field in corner portions of a trench bottom portion of a semiconductor device by implanting ions into the entire trench bottom portion
Data Source
Figure 1
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Figure 4
AI summary
A semiconductor device (100) comprises: a semiconductor substrate (1); a drift region (2) of a first conductivity type having a trench in part of an upper portion thereof and arranged on a first main surface of the semiconductor substrate (100); an electric field reducing region (4) of a second conductivity type arranged, in a bottom portion of the trench, only around a corner portion and not in a center portion; an anode electrode (9) embedded in the trench; and a cathode electrode (10) arranged on a second main surface of the semiconductor substrate (100) which is opposite to the first main surface.