GaN Power Transistor Threshold Voltage via AlGaN Barrier Segmentation
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Solution Overview
Problem
Existing GaN-based power transistors with two-dimensional electron gas (2DEG) architecture face challenges with low threshold voltage, requiring complex control circuits and increased on-state resistance, which degrades electrical current.
Innovation Solution
A GaN-based power transistor architecture with a stack of layers including a first AlGaN-based barrier, a GaN-based layer, and a second AlGaN-based barrier, where the gate pattern passes through the GaN-based layer and partially through the second AlGaN-based barrier, creating an additional potential barrier and electrostatic repulsion effect to increase the threshold voltage beyond 1V.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a second AlGaN-based barrier is added to increase threshold voltage, then the threshold voltage increases, but the on-state resistance increases
Solution Approach 1:
The patent applies local quality by creating a non-uniform AlGaN barrier structure where the barrier height and thickness vary laterally across the device. The barrier is stronger in regions where higher threshold voltage is needed while maintaining lower resistance paths in conduction regions, thus locally optimizing different functional requirements within the same structure.
Solution Approach 2:
The patent implements equipotentiality by designing the AlGaN barrier structure to create equal potential distribution in the on-state conduction path. The barrier is configured to maintain uniform electric field distribution when the device is on, reducing potential hotspots and minimizing on-state resistance while still providing sufficient threshold voltage in the off-state.
2Reliability
If the gate pattern passes through multiple AlGaN layers, then the threshold voltage control improves, but the device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the gate structure into distinct functional segments: a gate electrode portion, a gate dielectric portion, and an AlGaN barrier portion. Each segment performs a specific function - the electrode provides control voltage, the dielectric provides insulation, and the AlGaN barrier provides threshold voltage control. This segmentation allows independent optimization of each component while maintaining overall system reliability.
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 significantly increases the threshold voltage and reduces on-state resistance by forming a synergy between the physical and electrostatic barriers, allowing for simpler control circuits and improved electrical current handling.
Implementation Method 1
The two-dimensional electron gas is formed by piezoelectric and spontaneous polarisation effect under the first AlGaN-based barrier
Implementation Method 2
The two-dimensional electron gas is formed by piezoelectric and spontaneous polarisation effect under the first AlGaN-based barrier
Implementation Method 3
The threshold voltage is no longer only modulated by electrostatic repulsion effect, as is the case in the transistor disclosed by the solution of the prior art
Data Source
AI summary
A GaN-based power transistor including:a stack of layers in a vertical direction (z), the stack including, from an upper surface of the stack:a first AlGaN-based barrier),a GaN-based layer, anda second AlGaN-based barrier; anda gate pattern including:a metal gate, anda gate dielectric electrically insulating the metal gate from the stack, the metal gate being in contact with a bottom part and a wall part of the gate dielectric,the gate pattern passing through the first AlGaN-based barrier, then totally passing through the GaN-based layer and at least partially through the second AlGaN-based barrier, in the vertical direction (z), such that the second AlGaN-based barrier has a concentration of aluminium [Al]2 of less than or equal to 8% at.