Dual-Gate GaN Transistors Resolving On-Resistance and Breakdown Voltage Trade-offs
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Solution Overview
Problem
Existing GaN-based power transistors face challenges in achieving low on-resistance while maintaining high breakdown voltage, particularly in enhancement-mode devices, due to reduced channel mobility and limited gate-voltage swing, which complicates circuit designs and reliability.
Innovation Solution
A dual-gate normally-off nitride transistor is developed, featuring a first gate structure for controlling a normally-off channel region and a second gate structure for modulating a normally-on channel region, with the threshold voltage of the second gate being smaller than the drain breakdown of the first gate, allowing for efficient voltage modulation and reduced parasitics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If gate recess method is used to reduce channel resistance, then on-resistance is reduced, but breakdown voltage is also reduced
Solution Approach 1:
The device is divided into two distinct gate structures: a first gate (recessed) for controlling channel resistance and a second gate (non-recessed) for maintaining breakdown voltage. This segmentation allows each gate to be optimized independently for its specific function, resolving the contradiction between reducing on-resistance and maintaining high breakdown voltage.
Solution Approach 2:
Different regions of the device are given different properties: the first gate region has recessed structure for low resistance control, while the second gate region maintains original depth for high voltage support. This local differentiation enables simultaneous optimization of both on-resistance and breakdown voltage in different parts of the device.
2Ease of operation
If enhancement-mode transistors are used to simplify circuit designs, then ease of operation is improved, but on-resistance increases due to reduced channel mobility
Solution Approach 1:
The dual-gate structure segments the control functions: the first gate provides the enhancement-mode control for simplified circuit operation, while the second gate compensates for mobility reduction by providing additional channel modulation capability, thereby maintaining low on-resistance despite using E-mode operation.
3Speed
If gate length is reduced to reduce channel resistance, then on-resistance is reduced, but breakdown voltage is reduced
Solution Approach 1:
The channel is divided into two segments controlled by separate gates: the first gate controls a shorter channel segment for low resistance, while the second gate controls another segment that maintains the overall breakdown voltage. This allows the effective channel length for resistance to be shorter while the voltage support is maintained through the dual-gate configuration.
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 dual-gate design achieves low on-resistance and high breakdown voltage, simplifying circuit designs and improving system reliability, while reducing parasitic effects and enabling more efficient power conversion systems.
Implementation Method 1
a first gate structure formed between a source electrode and a drain electrode for controlling a normally-off channel region
Implementation Method 2
a second gate structure is formed between the first gate structure and the drain electrode for modulating a normally-on channel region underneath the second gate structure
Data Source
AI summary
A dual-gate normally-off nitride transistor that includes a first gate structure formed between a source electrode and a drain electrode for controlling a normally-off channel region of the dual-gate normally-off nitride transistor. A second gate structure is formed between the first gate structure and the drain electrode for modulating a normally-on channel region underneath the second gate structure. The magnitude of the threshold voltage of the second gate structure is smaller than the drain breakdown of the first gate structure for proper operation of the dual-gate normally-off nitride transistor.