GaN Power Devices with Interdigitated Electrodes for Thermal Management
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Solution Overview
Problem
Gallium nitride (GaN) based power devices face challenges with self-heating and inefficient heat dissipation, particularly in high-frequency and high-power applications, due to their small size and natural depletion mode operation, which limits their deployment in RF/microwave and power electronics.
Innovation Solution
The design incorporates a semiconductor device with interdigitated electrode fingers and a conductive channel on a die with tapered bases, arranged in a matrix on a PCB, allowing for efficient heat dissipation and improved thermal management by spreading heat uniformly across the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If GaN HEMTs are used for high-power applications, then power handling capability is improved, but self-heating becomes a major hindrance
Solution Approach 1:
The device is divided into multiple unit cells arranged in a lattice structure, with each unit cell containing individual semiconductor devices. This segmentation allows heat to be distributed across multiple discrete locations rather than concentrated in a single area, improving overall heat dissipation efficiency while maintaining high power handling capability
Solution Approach 2:
The patent transitions from conventional planar device layouts to a three-dimensional lattice structure where unit cells are arranged in multiple dimensions. This dimensional change enables heat to dissipate in multiple directions simultaneously, significantly improving thermal management while preserving the high power density of GaN devices
2Ease of operation
If multiple device or multiple die configurations are used to create E-mode devices, then depletion mode operation is improved, but heat dissipation efficiency deteriorates
Solution Approach 1:
The patent combines the E-mode and D-mode device functionalities into a single integrated GaN HEMT device structure, eliminating the need for separate series-connected devices or dies. This merging approach maintains the desirable E-mode operation characteristics while improving heat dissipation by concentrating thermal management resources in one device rather than spreading heat across multiple interfaces
Solution Approach 2:
The GaN HEMT device is designed to perform multiple functions within a single structure, including both the depletion mode operation control and the power switching functionality. This multi-functionality eliminates the need for additional series-connected devices, thereby reducing the overall device count and improving heat dissipation efficiency
3Ease of manufacture
If conventional layout topologies are used for flip-chip packaging, then manufacturing is simplified, but scalability and uniformity deteriorate
Solution Approach 1:
The lattice structure with unit cells arranged in a regular pattern provides a universal layout topology that can be scaled to different sizes while maintaining uniformity. This standardized arrangement facilitates flip-chip packaging by providing consistent bonding pad configurations, while simultaneously enabling scalability through simple replication of the unit cell pattern
Solution Approach 2:
The patent employs a modular unit cell design where the overall device dimensions can be adjusted by changing the number of unit cells in the lattice. This parameter change approach maintains the same fundamental layout topology and bonding pad configuration, ensuring uniformity across different device sizes while providing excellent scalability
Data Source
AI summary
Described herein are semiconductor devices and structures with improved power handling and heat dissipation. Embodiments are suitable for implementation in gallium nitride. Devices may be provided as individual square or diamond-shaped dies having electrode terminals at the die corners, tapered electrode bases, and interdigitated electrode fingers. Device matrix structures include a plurality of device dies arranged on a substrate in a matrix configuration with interdigitated conductors. Device lattice structures are based on a unit cell comprising a plurality of individual devices, the unit cells disposed on a chip with geometric periodicity. Also described herein are methods for implementing the semiconductor devices and structures.