Field Plate Electrode Segmentation for Power Semiconductor Voltage Trade-offs
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Solution Overview
Problem
Semiconductor devices with field plate structures face a trade-off between improving breakdown withstand voltage and reducing ON resistance, as the electric field is often concentrated at the p-n junction, leading to insufficient withstand voltage in some cases.
Innovation Solution
The semiconductor device incorporates a field plate electrode structure with alternating widths of field plate regions and insulating films, allowing for three-dimensional electric field relaxation and enhanced depletion layer extension, thereby increasing withstand voltage while maintaining high carrier concentrations and reducing ON resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a field plate electrode is provided below the gate electrode to relax electric field intensity in the drift region, then the breakdown withstand voltage between drain and source is improved, but the electric field becomes concentrated in the p-n junction part between the base region and the drift region, leading to insufficient withstand voltage in some cases
Solution Approach 1:
The field plate electrode is divided into multiple segments (first field plate electrode and second field plate electrode) separated by an insulating film. This segmentation allows the electric field to be distributed more evenly across the drift region, preventing concentration at the p-n junction while maintaining high breakdown withstand voltage.
Solution Approach 2:
An insulating film is introduced as an intermediary between the field plate electrode and the drift region. This insulating film modifies the electric field distribution by preventing direct field lines from concentrating at the p-n junction, thereby reducing electric field concentration while maintaining the voltage-blocking capability.
2Reliability
If the carrier density of the drift region is set to a high level to decrease the ON resistance, then the withstand voltage may be compromised due to electric field concentration, creating a trade-off relationship
Solution Approach 1:
The segmented field plate electrode structure enables independent optimization of different regions. The first and second field plate electrodes can be designed with different dimensions and positions, allowing the drift region to maintain high carrier density for low ON resistance while the segmented structure prevents electric field concentration that would compromise withstand voltage.
Solution Approach 2:
The field plate structure is designed with different local characteristics - the first field plate electrode has different dimensions than the second field plate electrode. This local quality variation allows optimal electric field distribution throughout the drift region, enabling high carrier density without sacrificing breakdown voltage.
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 effectively increases the breakdown withstand voltage and allows for high carrier concentrations, resulting in reduced ON resistance across the n-type drift region, improving the overall performance of the semiconductor device.
Implementation Method 1
electric field intensity in a drift region of the MOSFET is relaxed
Implementation Method 2
enhanced depletion layer extension
Data Source
AI summary
A semiconductor device includes first to third semiconductor regions, first to fourth electrodes and a first insulating film. The first insulating film is provided between the third electrode and the first semiconductor region, between the third electrode and the second semiconductor region, between the third electrode and the third semiconductor region, and between the fourth electrode and the first semiconductor region. The first insulating film has a first insulating region, a second insulating region and a third insulating region. A first width in the first insulating region is different from a second width in the second insulating region. The first insulating region and the second insulating region are arranged in the direction. A third width of the third insulating region is constant along the second direction.