Dual-Gate Nitride FET for Bidirectional Switching
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Solution Overview
Problem
Conventional nitride semiconductor FETs face challenges in achieving bidirectional switching operations due to low breakdown voltage and complex control requirements, making it difficult to realize a single-element bidirectional switch with high gate voltage capabilities and excellent reverse voltage characteristics.
Innovation Solution
A semiconductor device with a dual-gate structure, featuring a p-type control layer and a Schottky junction, allows for hole injection into the channel region, enabling modulation of carrier concentration and achieving a normally-off type operation with improved reverse voltage characteristics by using a dual-gate configuration and specific layer structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional nitride semiconductor FET is used, then the device structure is simple, but the breakdown voltage is low and bidirectional switching operation cannot be realized
Solution Approach 1:
The gate electrode is divided into two separate gates (first gate and second gate) that can be independently controlled. This segmentation allows each gate to handle different voltage polarities, enabling bidirectional switching with high breakdown voltage in both directions without requiring a completely new device architecture
Solution Approach 2:
The dual-gate FET structure provides multi-functionality by enabling the single device to operate as a bidirectional switch, perform four-quadrant control, and achieve both high breakdown voltage and normally-off characteristics. This universal structure replaces the need for multiple separate devices
2Reliability
If a plurality of elements are combined to realize bidirectional switching, then the breakdown voltage and bidirectional control capability are improved, but the control complexity and chip area increase
Solution Approach 1:
Multiple functions (bidirectional switching, high breakdown voltage, four-quadrant control) that would traditionally require multiple separate devices are merged into a single dual-gate FET structure. The two gates work cooperatively to provide all required functions, reducing control complexity and chip area compared to using multiple discrete elements
Solution Approach 2:
The dual-gate FET serves as a universal device that can perform bidirectional switching, handle both positive and negative voltages, and provide four-quadrant operation all within a single device structure, eliminating the need for complex multi-device configurations
3Reliability
If a normally-off type FET is used, then the safety in failure event is improved, but the gate voltage margin is narrow making the device sensitive to noise
Solution Approach 1:
The device maintains dynamic control over the channel through two independently controllable gates. This dynamic control allows the device to maintain normally-off characteristics for safety while the dual-gate structure provides sufficient voltage margin to overcome noise interference, as the gates can work together to establish a more robust threshold voltage
4Area of stationary object
If a single-element bidirectional switch is realized, then the chip area and cost are reduced, but the control in four quadrants and diode operation become difficult
Solution Approach 1:
The dual-gate structure provides dynamic control capability that enables the single device to adapt to different operating modes. By independently controlling the two gates, the device can operate in four-quadrant mode, function as a diode, or perform bidirectional switching, achieving high versatility within a compact single-element structure
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 semiconductor device effectively operates as a bidirectional switch with high gate voltage capabilities and excellent reverse voltage characteristics, enabling control in four quadrants and reducing the risk of erroneous operations due to noise, while minimizing chip area and cost.
Implementation Method 1
a first control layer having a p-type conductivity formed between the semiconductor layer stack and the first gate electrode
Implementation Method 2
allows for hole injection into the channel region, enabling modulation of carrier concentration
Implementation Method 3
A semiconductor device with a dual-gate structure, featuring a p-type control layer and a Schottky junction, allows for hole injection into the channel region, enabling modulation of carrier concentration and achieving a normally-off type operation
Data Source
AI summary
A semiconductor device includes a semiconductor layer stack 13 formed on a substrate 11 and having a channel region, a first electrode 16A and a second electrode 16B formed spaced apart from each other on the semiconductor layer stack 13, a first gate electrode 18A formed between the first electrode 16A and the second electrode 16B, and a second gate electrode 18B formed between the first gate electrode 18A and the second electrode 16B. A first control layer 19A having a p-type conductivity is formed between the semiconductor layer stack 13 and the first gate electrode 18A.