GaN HEMT Field Plate Dynamic Voltage Control
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Solution Overview
Problem
GaN-based high-electron-mobility transistors (HEMTs) experience current collapse phenomena at high frequencies and voltages, leading to increased on-resistance due to electron trapping, which is not adequately addressed by conventional field plates.
Innovation Solution
A transistor control circuit that applies a positive potential to a field plate electrode between the gate and drain, dynamically adjusting the voltage based on drain voltage conditions to mitigate electron trapping and reduce on-resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a field plate electrode is provided to moderate electric field amplification near the gate electrode, then current collapse phenomenon is mitigated, but on-resistance between source and drain increases at high frequencies and voltages
Solution Approach 1:
The field plate electrode's potential is changed dynamically from the conventional fixed source potential to a variable potential that changes according to the instantaneous drain voltage. This dynamic adjustment allows the field plate to actively counteract electron trapping effects during high-frequency and high-voltage operation, reducing on-resistance while maintaining current collapse mitigation.
Solution Approach 2:
The invention changes the key parameter of the field plate potential from a static value (source potential) to a dynamic value that varies with drain voltage. By setting the field plate potential to a value higher than the source potential based on instantaneous drain voltage conditions, the invention optimizes the electric field distribution to prevent electron trapping and reduce on-resistance during high-power operation.
2Loss of energy
If GaN-HEMT is operated at high frequency and high voltage, then power consumption and switching loss are reduced, but electron trapping occurs leading to increased on-resistance
Solution Approach 1:
The field plate electrode applies a preliminary positive potential before electrons can become trapped in the drain region during high-frequency switching. This preemptive action creates an electric field that prevents electron trapping from occurring in the first place, thereby maintaining low on-resistance during high-power operation where switching loss reduction is critical.
Solution Approach 2:
The field plate potential is determined based on instantaneous drain voltage, creating a feedback mechanism that responds to real-time operating conditions. This feedback control allows the system to dynamically adjust the field plate potential to counteract electron trapping effects that occur during high-frequency and high-voltage operation, maintaining optimal performance.
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 dynamic voltage control of the field plate effectively reduces on-resistance and stabilizes output by increasing two-dimensional electron gas concentration, improving the performance of GaN-HEMTs in high-frequency and high-voltage operations.
Implementation Method 1
free electrons become trapped in electron trap levels near the drain electrode side of the gate electrode
Implementation Method 2
A HEMT is a field-effect transistor incorporating a high-mobility two-dimensional electron gas (2DEG) induced by a semiconductor heterojunction as a channel
Implementation Method 3
moderate electric field amplification near the gate electrode
Data Source
AI summary
A transistor control circuit includes: an electrode control circuit configured to apply a positive potential to a control electrode in a transistor that includes the control electrode between a gate and a drain.