HEMT Gate-Drain Electrode Layout to Prevent Current Collapse
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Solution Overview
Problem
Lattice defects in III-V semiconductor compounds lead to electron trapping, causing current collapse in high electron mobility transistors (HEMTs), which affects device reliability.
Innovation Solution
An insulating layer is introduced between the drain and gate electrodes, with electrodes on this layer applying a voltage to attract and remove trapped electrons, preventing current collapse by neutralizing them when the HEMT is in the off state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If III-V semiconductor compounds are used to form HEMT channels, then high electron mobility and high frequency performance are achieved, but lattice defects occur during formation causing electron trapping and current collapse
Solution Approach 1:
An insulating layer is introduced as an intermediary between the drain electrode and gate electrode. This insulating layer contains trapping sites that capture electrons before they can be trapped by lattice defects in the semiconductor channel, thereby preventing current collapse while maintaining high electron mobility in the channel region
Solution Approach 2:
The patent converts the harmful effect of electron trapping by lattice defects into a beneficial mechanism by deliberately introducing trapping sites in the insulating layer. These controlled trapping sites capture electrons that would otherwise cause current collapse, transforming the harmful trapping phenomenon into a protective mechanism that enhances device reliability
2Reliability
If electrodes are added on the insulating layer to remove trapped electrons, then current collapse is prevented, but device structure becomes more complex
Solution Approach 1:
The insulating layer serves multiple functions: it provides electrical isolation between the drain and gate electrodes, contains trapping sites for electron capture, and supports additional electrodes for active electron removal. This multi-functionality allows the structure to prevent current collapse without requiring completely separate additional components
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 effectively removes trapped electrons, ensuring stable current flow in HEMTs by neutralizing them before the device is turned on, thereby enhancing the reliability and performance of HEMTs.
Implementation Method 1
by applying a voltage to the insulating layer, the trapped electrons can be removed
Implementation Method 2
A two-dimensional electron gas (2DEG) may be generated by the piezoelectric property of the GaN-based materials
Data Source
AI summary
A high electron mobility transistor includes a first III-V compound layer. A second III-V compound layer is disposed on the first III-V compound layer, wherein the composition of the first III-V compound layer and the second III-V compound layer are different from each other. A source electrode and a drain electrode are disposed on the second III-V compound layer. A gate electrode is disposed on the second III-V compound layer between the source electrode and the drain electrode. An insulating layer is disposed between the drain electrode and the gate electrode and covering the second III-V compound layer. Numerous electrodes are disposed on the insulating layer and contact the insulating layer, wherein the electrodes are positioned between the gate electrode and the drain electrode and a distribution of the electrodes decreases along a direction toward the gate electrode.