Semiconductor Device Trench Arrangement On-Resistance Reduction
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Solution Overview
Problem
The challenge in semiconductor devices is to reduce the on-resistance of the drift layer while maintaining a sufficient breakdown voltage, as deepening the trench and increasing the field plate insulating film thickness narrows the current path and hinders carrier movement, leading to increased on-resistance.
Innovation Solution
The semiconductor device incorporates a trench arrangement in a dot pattern, allowing for a wider drift layer and base region without being partitioned by trenches, with field plate electrodes extending vertically within the trenches to facilitate carrier flow and reduce on-resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the trench is deepened and the field plate insulating film thickness is increased to secure breakdown voltage, then the breakdown voltage is improved, but the current path of the drift layer is narrowed and on-resistance increases
Solution Approach 1:
The patent transitions from a conventional planar trench arrangement to a three-dimensional vertical trench structure. The trenches extend vertically through the drift layer to the substrate, creating depletion regions that provide breakdown voltage protection without narrowing the horizontal current path of the drift layer. This vertical dimension allows the field plate electrodes to extend along the trench walls, maintaining electrical field control while preserving the drift layer's current carrying capacity.
2Reliability
If the trench width is reduced to minimize impact on drift layer, then the breakdown voltage is maintained, but the carrier movement is hindered and on-resistance increases
Solution Approach 1:
The patent introduces field plate electrodes as intermediary structures that extend vertically along the trench walls. These field plate electrodes act as mediators that control the electrical field distribution and maintain breakdown voltage without requiring wide trenches. The field plate electrodes create a controlled depletion region that protects against breakdown while allowing carriers to move freely through the drift layer, eliminating the trade-off between breakdown voltage and carrier movement.
3Object-generated harmful factors
If the drift layer width is increased to reduce on-resistance, then the on-resistance is reduced, but the trench structure partitions the drift layer and limits the effective width
Solution Approach 1:
The patent segments the trench structure into multiple vertical columns distributed across the drift layer. Rather than using a single continuous trench that would partition the drift layer horizontally, the invention uses discrete vertical trenches that extend through the drift layer to the substrate. This segmentation allows the drift layer to maintain its horizontal continuity for current flow while the vertical trenches provide localized breakdown protection. The field plate electrodes within each trench further segment the electrical field control, allowing independent optimization of each region.
Data Source
AI summary
A semiconductor device includes a drain layer, a drift layer, a base region, a source region, trenches, base contact region, gate regions, and field plate electrodes. The drain layer extends in a first and a second direction. The drift layer is on the drain layer. The base region is on the drift layer. The source region is on the base region. The trenches are in an array and each trench reaches the drift layer from the source region. The base contact region is along the second direction in a region in which the trenches do not contiguously exist along the second direction and electrically connects the source region to the base region. Each gate regions is along an inner wall of the trenches. Each field plate electrodes is in an inside of the gate regions and is longer than the gate regions in the third direction.