GaN HEMT Second Barrier Layer for High Breakdown Voltage
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Solution Overview
Problem
Gallium nitride high electron mobility transistors (HEMTs) used as power devices have a low breakdown voltage due to gate electric field concentration and current leakage, limiting their application in high voltage and high power fields, and existing metal layer field plate structures introduce defects and degrade device quality.
Innovation Solution
A gallium nitride high electron mobility transistor with a second barrier layer configured to generate two-dimensional hole gas, positioned between the gate and drain, and connected to the gate's side wall, which improves the breakdown voltage by smoothing electric field distribution and reducing current leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a metal layer field plate structure is fabricated to smoothen the surface electric field distribution, then the breakdown voltage is improved, but defects and interface charge traps are introduced which degrade device quality and reliability
Solution Approach 1:
The patent changes the material parameter from metal to semiconductor (AlGaN) for the field plate structure, and changes the structural parameter from planar to suspended/overhanging configuration. This allows achieving field smoothing effect while avoiding metal-GaN interface defects and charge traps, thus improving both breakdown voltage and device reliability simultaneously
Solution Approach 2:
The patent uses a composite structure combining AlGaN barrier layer with suspended field plate configuration. The AlGaN material provides both the field smoothing effect and avoids the interface defect problems associated with metal layers, creating a composite solution that addresses both contradictions
2Strength
If the gate electric field concentration effect is not addressed, then the device structure remains simple, but the breakdown voltage remains low due to non-uniform electric field distribution
Solution Approach 1:
The patent segments the field plate structure into multiple components: AlGaN barrier layer, suspended field plate region, and drain contact region. This segmentation allows the field plate to be positioned strategically to smooth the electric field at the gate-drain junction without requiring complex overall device restructuring
Solution Approach 2:
The patent introduces a vertical/dimensional element by creating a suspended or overhanging field plate structure that extends over the drain region. This dimensional change allows the field plate to influence the electric field distribution in three-dimensional space, effectively smoothing the gate electric field concentration without planar complexity
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 solution significantly enhances the breakdown voltage of the HEMT, improving its reliability and stability for high voltage and high power applications by generating two-dimensional hole gas and reducing electric field peaks.
Implementation Method 1
a side wall of the second barrier layer being connected to a side wall on one side of the gate and being configured to generate two-dimensional hole gas
Data Source
AI summary
A gallium nitride high electron mobility transistor and a formation method therefor are provided. The transistor includes: a substrate; a gallium nitride channel layer disposed on the substrate; a first barrier layer disposed on the gallium nitride channel layer; a gate, a source and a drain disposed on the first barrier layer, the source and the drain being respectively disposed on two sides of the gate; and a second barrier layer disposed on a surface of the first barrier layer between the gate and the drain, a side wall of the second barrier layer being connected to a side wall on one side of the gate and being configured to generate two-dimensional hole gas. The high electron mobility transistor has a higher breakdown voltage.