HEMT Buffer Layer Structure for Heat Dissipation and Leakage Control
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Solution Overview
Problem
High Electron Mobility Transistors (HEMTs) face self-heating issues due to poor thermal conductivity of buffer layers, leading to accelerated device aging, degraded drain saturation current, and reduced carrier mobility, which conventional high crystallinity buffer layers exacerbate by increasing electron leakage.
Innovation Solution
A multilayer buffer layer structure is introduced, comprising alternating layers of high thermal conductivity buffer layers (e.g., aluminum nitride or boron nitride) and low-leakage layers (e.g., aluminum oxynitride or gallium nitride) to enhance heat dissipation while minimizing electron leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional high crystallinity buffer layers are used to improve thermal conductivity, then heat dissipation is enhanced, but electron leakage increases
Solution Approach 1:
The buffer layer is divided into multiple alternating layers with different materials and properties. The first buffer layer (AlN) provides high thermal conductivity for heat dissipation, while the second buffer layer (GaN or AlGaN) provides low electron leakage. This segmentation allows each layer to perform its specific function independently, resolving the contradiction between heat dissipation and electron leakage control.
2Duration of action of stationary object
If buffer layer thermal conductivity is increased to reduce self-heating, then device aging is slowed, but electron leakage increases
Solution Approach 1:
The buffer layer structure is segmented into alternating layers where the first buffer layer (AlN) with high thermal conductivity slows device aging by improving heat dissipation, while the second buffer layer (GaN or AlGaN) with low electron leakage maintains device reliability. This layered segmentation enables simultaneous achievement of both goals.
3Ease of manufacture
If single-layer buffer structure is used to simplify manufacturing, then fabrication process is easier, but thermal performance and leakage control cannot be optimized simultaneously
Solution Approach 1:
The buffer layer employs a composite structure consisting of alternating layers of different materials (AlN and GaN/AlGaN) with complementary properties. This composite approach allows the structure to simultaneously achieve high thermal conductivity from the AlN layers and low electron leakage from the GaN/AlGaN layers, optimizing both thermal performance and leakage control while maintaining compatibility with standard semiconductor fabrication processes.
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 multilayer buffer layer effectively dissipates heat, reducing device aging and maintaining thermal performance by balancing thermal conductivity and electron leakage, thus improving the reliability and efficiency of HEMTs.
Implementation Method 1
The first buffer layer has a first thermal conductivity and the second buffer layer has a second thermal conductivity, wherein the first thermal conductivity is greater than the second thermal conductivity
Implementation Method 2
the first buffer layer comprises a first material and the second buffer layer comprises a second material, wherein the first material has a lower electron leakage than the second material
Data Source
AI summary
Semiconductor devices and methods of forming the same are provided. A method of the present disclosure includes depositing an aluminum nitride layer over a substrate, treating the aluminum nitride layer to convert a top portion of the aluminum nitride layer to an aluminum oxynitride layer, depositing a III-V semiconductor layer on the aluminum oxynitride layer, and forming a gate structure over the III-V semiconductor layer.