Multi-Gate HEMT Structure for 2DEG Mode Switching
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Solution Overview
Problem
Conventional high electron mobility transistors (HEMTs) can only exist in either enhancement-mode or depletion-mode designs, lacking the ability to combine both advantages simultaneously.
Innovation Solution
A high electron mobility transistor design that includes a substrate, buffer layer, channel layer, and epitaxial structures with specific layer configurations and fabrication methods, allowing for the formation of both enhancement-mode and depletion-mode characteristics by controlling the 2DEG channel through voltage application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a HEMT is designed as enhancement-mode, then the 2DEG channel can be opened by applying positive voltage to achieve effective control, but the transistor cannot maintain the channel open without gate voltage like depletion-mode devices
Solution Approach 1:
The gate structure is segmented into multiple independent gates (first gate and second gate) that can be controlled separately. This allows the transistor to operate in different modes by applying different voltage combinations to the segmented gates, enabling both enhancement-mode and depletion-mode functionality within a single device structure.
Solution Approach 2:
The transistor operates dynamically by switching between different gate voltage states. The first gate controls the formation of the 2DEG channel (enhancement-mode operation), while the second gate can deplete the channel (depletion-mode operation). This dynamic control allows the device to adapt its operating mode based on application requirements.
2Quantity of substance
If a HEMT is designed as depletion-mode, then the 2DEG channel remains open without gate voltage and electron concentration can be increased through barrier layer design, but the transistor cannot achieve effective voltage control like enhancement-mode devices
Solution Approach 1:
The gate structure is segmented into multiple independent gates (first gate and second gate) that can be controlled separately. This allows the transistor to operate in different modes by applying different voltage combinations to the segmented gates, enabling both enhancement-mode and depletion-mode functionality within a single device structure.
Solution Approach 2:
The operating mode is changed by varying the gate voltage parameters. The first gate voltage controls electron concentration and channel formation, while the second gate voltage adjusts the depletion level. By changing these voltage parameters, the transistor can switch between high electron concentration states and voltage-controlled states.
3Reliability
If separate enhancement-mode and depletion-mode HEMTs are used, then each mode's advantages can be utilized, but the device complexity and control circuit requirements increase
Solution Approach 1:
The patent merges enhancement-mode and depletion-mode functionalities into a single HEMT device structure. By integrating multiple gates that can be independently controlled, the device combines the advantages of both modes (effective voltage control and high electron concentration) without requiring separate transistors, thereby reducing overall system complexity.
Solution Approach 2:
The HEMT structure is designed to be universal, capable of performing both enhancement-mode and depletion-mode operations. The multi-gate configuration enables the single device to fulfill multiple functional roles, eliminating the need for separate specialized devices and simplifying the control circuitry.
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 transistor achieves increased electron concentration and effective control of the 2DEG channel, combining the advantages of both enhancement-mode and depletion-mode HEMTs, reducing control circuit complexity and enhancing performance.
Implementation Method 1
The high electron mobility transistor (HEMT) is a field effect transistor that uses semiconductor materials with different energy gaps to form a two-dimensional electron gas (2D electron gas, 2DEG for short) layer at the junction
Implementation Method 2
The first semiconductor epitaxial structure is located on the channel layer and sequentially includes a first aluminum gallium nitride layer, a supply layer and a second aluminum gallium nitride layer
Data Source
AI summary
The present invention provides a high electron mobility transistor, which includes a substrate, a buffer layer, a channel layer, a first semiconductor epitaxial structure, a second semiconductor epitaxial structure, a drain, a source and a gate. The first semiconductor epitaxial structure is located on the channel layer and sequentially includes a first aluminum gallium nitride layer, a supply layer and a second aluminum gallium nitride layer, and the first semiconductor epitaxial structure is formed with a hollow part extending from a top surface of the second aluminum gallium nitride layer toward the channel layer. The second semiconductor epitaxial structure is located in the hollow part and sequentially includes an aluminum gallium nitride layer and a P-type gallium nitride layer. The drain and the source are respectively arranged on the second aluminum gallium nitride layer, and the gate is arranged on the P-type gallium nitride layer.