Sandwich-Structure GaN-HEMT for Higher Breakdown Voltage
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Solution Overview
Problem
Current GaN-HEMT devices face limitations in breakdown voltage and gate voltage swing due to the traditional single-gate bar structure, which restricts the improvement of linearity and pressure-resistance properties.
Innovation Solution
A GaN-HEMT device with a sandwich structure is developed, featuring a GaN channel layer and an AlGaN barrier layer, where a field plate electrode extends beyond the epitaxial layer and is connected to the gate electrode, enhancing control over the two-dimensional electron gas and improving breakdown voltage and gate voltage swing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional single-gate bar structure is adopted, then device fabrication is simple, but breakdown voltage and gate voltage swing are limited
Solution Approach 1:
The gate structure is segmented into two independent gates (first gate electrode and second gate electrode) positioned at opposite sides of the channel, allowing each gate to independently control different portions of the two-dimensional electron gas. This segmentation enables enhanced breakdown voltage through dual-gate control while maintaining fabrication simplicity by using symmetric structures
Solution Approach 2:
The invention transitions from a single-gate planar structure to a dual-gate structure where gates are positioned at opposite sides of the channel (adding spatial dimensionality). This dimensional change allows simultaneous control of breakdown voltage and gate voltage swing through independent gate biases, resolving the limitation of single-gate structures
2Adaptability or versatility
If traditional single-gate bar structure is adopted, then device structure is simple, but linearity and pressure-resistance properties are limited
Solution Approach 1:
The channel control is segmented into two independent gate regions, allowing differential control of electron gas density across the channel. This enables superior linearity through independent optimization of each gate's voltage swing characteristics while maintaining overall structural simplicity
Solution Approach 2:
The dual-gate structure provides multi-functionality by enabling independent control of breakdown voltage, gate voltage swing, and linearity through separate gate biases. Both gates work simultaneously to achieve multiple performance objectives without requiring additional complex components
3Reliability
If field effect is applied in single direction, then device structure is simple, but improvement of breakdown voltage and linearity is limited
Solution Approach 1:
The field effect control is segmented into two independent directional controls, with each gate applying field effect from its respective side. This dual-directional field control enhances breakdown voltage by suppressing carrier injection from both source and drain simultaneously, while improving ease of operation through independent gate voltage adjustment
Solution Approach 2:
The two gates provide counterbalancing field effects that work together to enhance breakdown voltage. By applying opposite polarity biases to the two gates, the structure creates symmetric field distribution that reinforces breakdown voltage improvement while maintaining operational simplicity
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 sandwich structure increases breakdown voltage and gate voltage swing, while maintaining high linearity and pressure-resistance properties, as demonstrated by increased breakdown voltage and improved gate voltage swing in three-terminal tests compared to planar structures.
Implementation Method 1
under the modulation of polarized electric field, two-dimensional electron gas with an area density of 1013 cm−2 can be formed at the heterointerface
Implementation Method 2
AlGaN/GaN heterojunction is formed by epitaxy
Implementation Method 3
the field plate electrode extends to a region beyond the epitaxial layer and is connected with the gate electrode to form the sandwich structure
Data Source
AI summary
A GaN-HEMT device with a sandwich structure and a method for preparing the same are provided. The GaN-HEMT device includes an epitaxial layer and electrodes, wherein the epitaxial layer includes a GaN channel layer (2) and an AlyGa1-y barrier layer (1), and is arranged from top to bottom; the electrodes include a gate electrode (6), a source electrode (7), a drain electrode (5) and a field plate electrode (10), wherein the field plate electrode (10) and the gate electrode (6) are respectively fabricated on an upper surface and a lower surface of the epitaxial layer, and the field plate electrode (10) extends to a region beyond the epitaxial layer and is connected with the gate electrode (6) to form the sandwich structure, and the source electrode (7) and the drain electrode (5) are respectively located at two ends of the epitaxial layer.