Anti-Series GaN Bidirectional Switch for Stable High-Speed Switching
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Solution Overview
Problem
Bidirectional switches using GaN lateral transistors face stability issues in their switching operations, which existing technologies have not adequately addressed.
Innovation Solution
A bidirectional switch device incorporating two lateral transistor chips connected in anti-series, with each chip having a semiconductor layer formed on a substrate and electrodes connected to conductive dies and conductive layers, stabilizes the potential and reduces capacitance, allowing for more stable and efficient switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If lateral transistors are used in a bidirectional switch, then switching rate is improved, but switching operation stability deteriorates
Solution Approach 1:
The invention connects the substrate of each lateral transistor to the source electrode with different potential through a conductive layer, equalizing the potential between substrate and source electrode. This eliminates potential differences that cause instability, while preserving the high switching rate advantage of lateral transistors. The conductive layer ensures both substrate and source electrode are at the same potential, resolving the stability issue without sacrificing switching performance.
2Reliability
If vertical transistors are used in a bidirectional switch, then switching operation stability is improved, but switching rate deteriorates
Solution Approach 1:
The invention applies equipotentiality to lateral transistors by connecting the substrate to the source electrode through a conductive layer, making their potential equal. This enables lateral transistors to achieve the stability of vertical transistors while maintaining their inherent high switching rate advantage, effectively resolving the trade-off between stability and switching speed.
3Device complexity
If the substrate and source electrode are at different potentials, then transistor operation is simplified, but capacitance increases and stability decreases
Solution Approach 1:
The conductive layer connects the substrate to the source electrode, equalizing their potentials. This reduces the capacitance between them and eliminates the stability problems caused by potential differences, while the transistor operation remains simple through standard gating control.
4Reliability
If the substrate and source electrode are connected to equalize potentials, then stability is improved, but device complexity increases
Solution Approach 1:
The conductive layer serves as an intermediary element that connects the substrate to the source electrode. This simple conductive structure equalizes potentials between the two components, improving stability without significantly increasing device complexity. The conductive layer is a straightforward electrical connection that integrates seamlessly into the existing transistor structure.
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
An object of the present invention is to provide a bidirectional switch with the ability to perform its switching operation with increased stability and also provide a bidirectional switch device including such a bidirectional switch. A bidirectional switch (8a) includes: a first lateral transistor (1) including a first semiconductor layer (11) on the surface of a first conductive layer (10); a second lateral transistor (2) including a second semiconductor layer (21) on the surface of a second conductive layer (20); a connection member (5a); a first conductor member (61a); and a second conductor member (62a). The connection member (5a) connects the first lateral transistor (1) and the second lateral transistor (2) together in anti-series. The first conductor member (61a) electrically connects the first source electrode (IS) of the first lateral transistor (1) to the first conductive layer (10). The second conductor member (62a) electrically connects the second source electrode (2S) of the second lateral transistor (2) to the second conductive layer (20).