Bidirectional JFET Trench Gate and Field Electrode Design
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Solution Overview
Problem
Bidirectional transistors, particularly power metal-oxide-semiconductors field-effect transistors (MOSFETs), face limitations in their performance characteristics such as on-state resistance, necessitating further improvement for enhanced performance in applications like electric vehicle battery charging.
Innovation Solution
The development of a bidirectional junction field-effect transistor (JFET) with a unique structure involving a drain/source region, a lightly doped semiconductor layer, a source/drain region, trenches, gate electrodes, and field electrodes, which allows for improved on-state resistance and drain-to-source breakdown voltage through optimized doping and electrode configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If power MOSFETs are used for bidirectional transistors, then the device can be manufactured with existing processes, but the on-state resistance is limited and performance is constrained
Solution Approach 1:
The device is segmented into distinct functional regions including a drift region, a first doped region, a second doped region, and a third doped region. This segmentation allows each region to be optimized independently for its specific function, enabling lower on-state resistance while maintaining manufacturability through standardized process modules.
Solution Approach 2:
Different doping concentrations and types are applied to different regions of the semiconductor structure. The drift region has one doping profile, while the first, second, and third doped regions have different doping characteristics. This local quality optimization enables simultaneous improvement of on-state resistance and breakdown voltage without compromising manufacturability.
Data Source
AI summary
An electronic device comprising a bidirectional JFET can include a drain/source region; a lightly doped semiconductor layer overlying the drain/source region; a source/drain region overlying the lightly doped semiconductor layer; a trench extending through the source/drain region and into the lightly doped semiconductor layer; a gate electrode of the bidirectional JFET within the trench; and a field electrode within the trench. A process of forming an electronic device can include providing a workpiece including a first doped region and a lightly doped semiconductor layer overlying the first doped region; defining a trench extending into the lightly doped semiconductor layer; forming a gate electrode within the trench, wherein the gate electrode extends to a sidewall of the trench; and forming a field electrode within the trench, wherein a bidirectional JFET includes the first doped region, the lightly doped semiconductor layer, a second doped region, and the gate electrode.