Breakdown Voltage Blocking Device Trench Structure
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Solution Overview
Problem
Current high voltage MOSFET devices, such as Super Junction MOSFETs, are challenging to manufacture due to their complex structure, which includes multiple P-type vertical junction column regions in the core drift region, making them difficult to produce effectively.
Innovation Solution
A breakdown voltage blocking device is designed with an epitaxial region above a substrate, featuring source trenches and a gate trench with dielectric and conductive regions, allowing for the control of voltage blocking capabilities by adjusting the depth and doping of these structures, enabling the device to handle high voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Super Junction MOSFET structure is used to achieve high voltage handling capability, then voltage blocking capability is improved, but manufacturing difficulty increases due to complex P-type vertical junction column regions
Solution Approach 1:
The patent extracts the voltage blocking function from the complex Super Junction structure and implements it through a separate breakdown voltage blocking device with trenches filled with dielectric material and conductive regions. This removes the need for multiple P-type vertical junction column regions while achieving the same high voltage blocking capability, thereby simplifying manufacturing.
Solution Approach 2:
The patent introduces an intermediary breakdown voltage blocking device that sits between the MOSFET and the high voltage environment. This device uses dielectric layers and conductive regions as mediators to block voltage, avoiding the need for complex P-type vertical junctions in the MOSFET itself and making manufacturing easier.
2Reliability
If multiple P-type vertical junction column regions are added to increase voltage handling capability, then voltage blocking capability is improved, but device complexity increases
Solution Approach 1:
The patent segments the voltage blocking function into separate components: trenches filled with dielectric material and conductive regions positioned at specific depths. This segmentation replaces the complex multiple P-type vertical junction column regions with a simpler, modular structure that achieves the same voltage handling capability without increasing device complexity.
Solution Approach 2:
The patent transitions from vertical P-type junction columns to a horizontal trench-based structure with dielectric and conductive regions. By changing the dimensional approach from vertical stacking of doped regions to horizontal trenches filled with materials, the patent reduces structural complexity while maintaining voltage blocking performance.
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
The solution allows for the creation of MOSFET devices capable of handling high voltages, such as 600 volts, by optimizing the depth and doping of the epitaxial region and dielectric layers within the trenches, enhancing the device's voltage blocking capabilities and manufacturing ease.
Implementation Method 1
Each source trench can include a dielectric layer surrounding a conductive region. The gate trench can include a dielectric layer that lines the sidewalls and bottom of the gate trench
Implementation Method 2
Each source trench can include a dielectric layer surrounding a conductive region. The gate trench can include a dielectric layer that lines the sidewalls and bottom of the gate trench and a conductive region located between the dielectric layer
Data Source
AI summary
In one embodiment, a breakdown voltage blocking device can include an epitaxial region located above a substrate and a plurality of source trenches formed in the epitaxial region. Each source trench can include a dielectric layer surrounding a conductive region. The breakdown voltage blocking device can also include a contact region located in an upper surface of the epitaxial region along with a gate trench formed in the epitaxial region. The gate trench can include a dielectric layer that lines the sidewalls and bottom of the gate trench and a conductive region located between the dielectric layer. The breakdown voltage blocking device can include source metal located above the plurality of source trenches and the contact region. The breakdown voltage blocking device can include gate metal located above the gate trench.