Pectinate Trench MOSFET Channel Width
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Solution Overview
Problem
Conventional trench MOSFET devices face challenges in reducing channel resistance and on-state resistance due to limitations in increasing the width of the channel, as the conventional strip-type or square-type trenches restrict further widening of the channel length, making it difficult to decrease channel resistance effectively.
Innovation Solution
The introduction of a pectinate trench structure with a plurality of tooth trenches and a bar trench interconnecting them, which increases the width of the channel and reduces channel resistance by allowing for a greater width within the same length, thereby decreasing on-state resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional strip-type or square-type trenches are used, then the manufacturing process is simple, but the channel width cannot be increased further, making it difficult to decrease channel resistance
Solution Approach 1:
The conventional single trench structure is segmented into multiple tooth trenches arranged in a comb-like pattern. This segmentation allows the channel width to be increased by adding more tooth trenches without significantly complicating the manufacturing process, as all trenches can be formed using the same etching methodology.
Solution Approach 2:
The trench structure transitions from a simple linear or square configuration to a multi-dimensional comb-like arrangement with tooth trenches extending in multiple directions. This dimensional change enables significant increase in channel width within the same device footprint, thereby reducing channel resistance while maintaining manufacturability.
2Manufacturing precision
If the density of cells is fixed, then decreasing channel resistance can effectively decrease on-state resistance, but conventional trenches restrict further widening of the channel
Solution Approach 1:
Multiple tooth trenches are merged into a single integrated pectinate trench structure that functions as one continuous channel region. This merging approach increases the effective channel width and reduces on-state resistance while avoiding the need for separate processing steps for each individual trench, thus not increasing device complexity.
3Manufacturing precision
If the length of the channel is fixed, then widening the width of the channel can decrease channel resistance, but conventional strip-type or square-type trenches make it difficult to increase the width
Solution Approach 1:
The trench structure utilizes a comb-like configuration that expands the channel width by adding tooth trenches in a pattern that efficiently uses the available cell area. This dimensional arrangement allows significant width increase without proportionally increasing the overall cell area, thereby reducing channel resistance while maintaining compact device dimensions.
Data Source
AI summary
A trench Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) device is disclosed. The trench MOSFET device includes a substrate, a body region, a source region, a dielectric layer, a metal layer, a contact hole, and a trench structure. The substrate includes a substrate layer and an epitaxial layer formed on the substrate layer; the body region is formed in the epitaxial layer; and the source region is formed in the body region of the epitaxial layer. Further, the dielectric layer is formed on the epitaxial layer; the metal layer is formed on the dielectric layer; and the contact hole is formed in the dielectric layer to connect the source region with the metal layer. In addition, the trench structure is formed in the epitaxial layer, and the trench structure includes a first trench that is a pectinate trench including a plurality of tooth trenches and a bar trench interconnecting the plurality of tooth trenches.