GaN HEMT With Integrated Avalanche Diode for Surge Protection
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Solution Overview
Problem
High-voltage applications, such as automotive electric control units, require power devices with avalanche diodes that have recoverable breakdown capability to protect against high voltages and currents, which existing GaN-based HEMTs lack due to the absence of built-in avalanche diodes.
Innovation Solution
A semiconductor device is developed that integrates a GaN-based high electron mobility transistor (HEMT) with a monolithically integrated avalanche diode on the same semiconductor die, where the diode is electrically coupled to the source and drain of the HEMT, providing avalanche capability and protecting the device from high voltage and current surges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If GaN-based HEMT is used for high-voltage applications, then high breakdown field and high electron mobility are achieved, but avalanche breakdown capability is lost
Solution Approach 1:
The patent merges the HEMT and avalanche diode into a single integrated device structure. The diode is formed within the same semiconductor layer stack as the HEMT, with the anode connected to the source and cathode connected to the drain. This integration allows the device to simultaneously achieve high breakdown field (from the HEMT) and avalanche breakdown capability (from the integrated diode), resolving the contradiction between strength and reliability.
2Loss of energy
If HEMT and diode are integrated on the same die, then parasitic resistance and inductance are reduced, but device complexity increases
Solution Approach 1:
The HEMT and diode are merged into a single monolithic structure formed from the same semiconductor layer stack. The diode shares the same substrate and semiconductor layers as the HEMT, with the anode connected to the source region and cathode connected to the drain region. This merging eliminates the need for separate discrete components and interconnections, thereby reducing parasitic resistance and inductance while the integrated formation process manages the complexity.
Solution Approach 2:
The semiconductor layer stack serves multiple functions simultaneously: it forms both the HEMT active region and the avalanche diode structure. The same AlGaN/GaN heterostructure provides both the high-electron-mobility channel for the HEMT and the breakdown characteristic for the avalanche diode. This multi-functionality reduces the need for additional separate components, managing device complexity while achieving energy loss reduction.
3Reliability
If separate discrete devices are used for HEMT and avalanche diode, then device functionality is achieved, but device size and cost increase
Solution Approach 1:
The patent combines the HEMT and avalanche diode into a single integrated device on one semiconductor die. The diode is formed within the same AlGaN/GaN layer stack as the HEMT, eliminating the need for separate discrete devices. This integration maintains the avalanche protection functionality while significantly reducing the overall device size by eliminating separate components, packaging, and interconnections.
Solution Approach 2:
The AlGaN/GaN semiconductor layer stack is designed to provide multiple functions simultaneously: it creates the high-electron-mobility channel for the HEMT and also forms the avalanche diode structure for protection. This multi-functional design eliminates the need for separate avalanche protection devices, reducing device size while maintaining the required reliability for avalanche protection.
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 integration of the HEMT and avalanche diode on the same die reduces parasitic resistance and inductance, leading to shorter response times and improved high-speed switching performance, while also reducing costs and device size.
Implementation Method 1
a channel formed at an AlGaN/GaN heterostructure
Implementation Method 2
a two-dimensional electron gas (2DEG) channel formed at a heterostructure interface
Implementation Method 3
a diode formed in the substrate or in the semiconductor layer stack... providing avalanche capability and protecting the device from high voltage and current surges
Data Source
AI summary
A semiconductor device includes a substrate, a semiconductor layer stack on the substrate, and a gate, a source, and a drain formed on or in the semiconductor layer stack. The semiconductor layer stack may include a non-silicon channel layer and a barrier layer on the channel layer. At least one of the substrate or the semiconductor layer stack includes a diode, a first terminal of the diode electrically coupled to the source, and a second terminal of the diode electrically coupled to the drain.