GaN Device Thermal Management via Staggered Cell Layout
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Solution Overview
Problem
Gallium nitride material devices face challenges in thermal management, as increased device temperature leads to reduced carrier mobility, sheet charge density, and higher leakage currents, limiting their ability to operate at high power densities.
Innovation Solution
The design involves arranging transistors in cells with optimized spacing and staggered configurations, along with thermally conductive packaging and selective substrate removal to enhance heat conduction, including the use of vias and thermally conductive material regions to improve thermal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If transistors are arranged with smaller inter-cell spacing to increase device density, then productivity is improved, but thermal management deteriorates due to increased heat generation and reduced heat dissipation capability
Solution Approach 1:
The device is divided into multiple cells with optimized inter-cell spacing. Each cell contains transistors arranged in a systematic pattern, and the spacing between cells is specifically designed to balance density with thermal management. This segmentation allows heat to be distributed and dissipated more effectively across the device structure.
Solution Approach 2:
Different regions of the device have different inter-cell spacing configurations. The spacing is optimized locally based on thermal considerations, with greater spacing in regions requiring better heat dissipation and tighter spacing in regions where density is prioritized. This local optimization resolves the contradiction between overall density and local thermal management.
2Ease of manufacture
If transistors are arranged in a grid pattern to simplify manufacturing, then ease of manufacture is improved, but thermal conduction deteriorates due to aligned heat generation paths
Solution Approach 1:
The transistor cells are arranged in a staggered configuration rather than a symmetric grid pattern. This asymmetric arrangement disrupts the alignment of heat generation paths, allowing heat to conduct more effectively through the substrate without concentrated thermal channels. The staggered pattern maintains manufacturing simplicity while significantly improving thermal conduction characteristics.
3Productivity
If gate pitch is reduced to increase transistor density, then productivity is improved, but thermal resistance increases due to closer heat generation sources
Solution Approach 1:
The solution addresses thermal resistance not only in the lateral plane but also in the vertical dimension. By optimizing the three-dimensional heat conduction paths and utilizing the substrate thickness and packaging structure, the invention effectively manages thermal resistance even with reduced gate pitch and increased transistor density.
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
This approach reduces thermal resistance, enabling gallium nitride material devices to operate at high power densities while maintaining excellent electrical properties, increasing reliability and lifetime.
Implementation Method 1
The design involves arranging transistors in cells with optimized spacing and staggered configurations, along with thermally conductive packaging and selective substrate removal to enhance heat conduction
Data Source
AI summary
Gallium nitride material devices and methods associated with the devices are described. The devices may be designed to provide enhanced thermal conduction and reduced thermal resistance. The increased thermal conduction through and out of the gallium nitride devices enhances operability of the devices, including providing excellent RF operation, reliability, and lifetime.