GaN Half-Bridge Transistor Isolation for Stable Substrate Potential
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Solution Overview
Problem
GaN HEMT devices in half-bridge structures are susceptible to changes in current collapse characteristics and gate threshold due to potential mismatches between the source potential and substrate potential, especially when the Si substrate is electrically connected to the source electrode.
Innovation Solution
A nitride semiconductor device configuration with insulating regions between lateral transistors on a substrate, including separation trenches and insulators, to isolate and stabilize the substrate potential, ensuring consistent current collapse characteristics and gate thresholds across the half-bridge circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the Si substrate is electrically connected to the source electrode to keep the substrate potential unchanged, then the device can operate as a lateral structure suitable for half-bridge integration, but changes in current collapse characteristics or gate threshold occur due to potential mismatch between source potential and substrate potential
Solution Approach 1:
The substrate is divided into first and second regions with different electrical connection configurations. The first region connects the Si substrate to the source electrode, while the second region uses an insulating region to isolate the substrate, creating segmented potential zones that prevent potential mismatch effects
Solution Approach 2:
An insulating region is introduced as an intermediary element between the Si substrate and the second region. This insulating region acts as a mediator that isolates the substrate potential from affecting the transistor characteristics, preventing the harmful potential mismatch
2Productivity
If the Si substrate is electrically connected to the source electrode, then single-chip integration for half-bridge structure is enabled, but mismatch between source potential and substrate potential causes changes in gate threshold
Solution Approach 1:
The substrate is segmented into first and second regions with different electrical connection configurations. The first region allows substrate connection for integration, while the second region isolates the substrate to maintain gate threshold consistency
Solution Approach 2:
Different electrical connection qualities are applied to different regions of the substrate. The first region has direct substrate connection while the second region has insulating isolation, allowing each region to have optimized characteristics for its specific function
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 configuration effectively suppresses changes in current collapse characteristics and gate thresholds, enabling stable operation of nitride semiconductor devices in half-bridge circuits by maintaining consistent substrate potential and electrical characteristics between transistors.
Implementation Method 1
A first insulating region is disposed between a portion corresponding to the first region on the substrate and a portion corresponding to the second region on the substrate
Data Source
AI summary
The present invention provides a nitride semiconductor device, including an insulating substrate, a substrate over the first surface of the insulating substrate, a first lateral transistor over a first region of the substrate, wherein the first lateral transistor includes a first nitride semiconductor layer formed over the substrate, and a first gate electrode, a first source electrode and a first drain electrode formed over the first nitride semiconductor layer, and a second lateral transistor over a second region of the substrate, wherein the second lateral transistor includes a second nitride semiconductor layer formed over the substrate, and a second gate electrode, a second source electrode and a second drain electrode formed over the second nitride semiconductor layer, and a separation trench formed over a third region, wherein the third region is between the first region and the second region.