Vertical GaN Transistor Using Polarization Heterojunctions for High Power
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Solution Overview
Problem
Current GaN-based electronics using lateral HEMT technology are limited by small channel width, restricting high voltage and high current operations, while Si-based power electronics suffer from low switching frequencies, higher losses, and poor high-temperature performance.
Innovation Solution
A transistor design utilizing a vertical architecture with a thick, low-doped drift region and a polarization heterojunction and pn junction formed by group III-nitride semiconductor layers, enabling high voltage and current handling through a true vertical device architecture with wide current channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If lateral HEMT architecture is used, then high frequency switching is achieved, but channel width is limited restricting high voltage and high current operations
Solution Approach 1:
The patent transitions from a lateral HEMT architecture to a vertical HEMT architecture, changing the current flow direction from lateral to vertical. This dimensional change allows the channel to extend through the thickness of the semiconductor layers rather than being constrained laterally, enabling both high switching frequency and high voltage/current operations simultaneously.
2Ease of manufacture
If silicon-based power devices are used, then cost advantage is achieved, but switching frequencies are low and losses are high
Solution Approach 1:
The patent changes the material parameter from silicon to group III-nitride semiconductors (such as GaN), which have fundamentally different electrical properties including higher electron mobility and wider bandgap. This material parameter change enables high switching frequencies while maintaining cost-effectiveness through compatibility with existing semiconductor manufacturing processes.
3Ease of manufacture
If silicon-based power devices are used, then cost advantage is achieved, but high-temperature performance is poor
Solution Approach 1:
The patent employs composite material structures consisting of multiple group III-nitride semiconductor layers with different compositions and properties (such as AlGaN/GaN heterostructures). These composite structures provide both thermal stability for high-temperature operation and electrical performance, while remaining compatible with cost-effective manufacturing approaches.
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
Enables high power operation with voltage capabilities exceeding 600 V and current handling exceeding 10 amps, suitable for applications like electric vehicles and renewable energy systems, while improving thermal management and switching performance.
Implementation Method 1
An interface between the second layer and the third layer form a polarization heterojunction
Implementation Method 2
An interface between the third layer and the fourth layer forms a pn junction
Data Source
AI summary
A transistor includes a first layer comprising a group III-nitride semiconductor. A second layer comprising a group III-nitride semiconductor is disposed over the first layer. A third layer comprising a group III-nitride semiconductor is disposed over the second layer. An interface between the second layer and the third layer form a polarization heterojunction. A fourth layer comprising a group III-nitride semiconductor is disposed over the third layer. An interface between the third layer and the fourth layer forms a pn junction. A first electrical contact pad is disposed on the fourth layer. A second electrical contact pad is disposed on the third layer. A third electrical contact pad is electronically coupled to bias the polarization heterojunction.