Trench MOSFET Gate Segmentation for Reduced Die Size
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Solution Overview
Problem
In optimizing MOSFET performance, existing device structures and fabrication processes often result in trade-offs where improving one parameter, such as figure of merit, leads to degradation in other parameters like die size, making it challenging to achieve optimal performance.
Innovation Solution
The formation of electronic devices with trenches and conductive structures where half of the gate electrodes are replaced by conductive structures, reducing total gate charge and on-resistance, thereby improving performance and allowing for a smaller die size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conventional trench power MOSFET structures are used, then device performance is maintained, but die size is larger and packaging flexibility is reduced
Solution Approach 1:
The gate structure is segmented into two types: conventional gate electrodes in first trenches and conductive structures without gate electrodes in second trenches. This segmentation allows different regions to serve different functions, reducing overall die size while maintaining performance through the selective placement of gate structures.
Solution Approach 2:
Different regions of the device are assigned different structures: areas requiring high performance have conventional gate electrodes, while areas where size reduction is prioritized have conductive structures without gate electrodes. This local differentiation optimizes the balance between performance and size.
2Reliability
If more gate electrodes are used, then device performance improves, but total gate charge increases
Solution Approach 1:
Gate electrodes are extracted (removed) from certain trenches and replaced with conductive structures only. This reduction in the number of gate electrodes directly decreases total gate charge while maintaining adequate device performance through the remaining gate structures.
Solution Approach 2:
Instead of providing gate electrodes in all trenches (excessive action), gate electrodes are provided only in selected trenches (partial action). This partial implementation is sufficient to achieve the desired performance while significantly reducing gate charge.
Data Source
AI summary
An electronic device can include a transistor structure, including a patterned semiconductor layer overlying a substrate and having a primary surface, wherein the patterned semiconductor layer defines a first trench and a second trench that extend from the primary surface towards the substrate. The electronic device can further include a first conductive electrode and a gate electrode within the first trench. The electronic device can still further include a second conductive electrode within the second trench. The electronic device can include a source region within the patterned semiconductor layer and disposed between the first and second trenches. The electronic device can further include a body contact region within the patterned semiconductor layer and between the first and second trenches, wherein the body contact region is spaced apart from the primary surface. Processes of forming the electronic device can take advantage of forming all trenches during processing sequence.