HEMT Current Limiting Structure for Short Circuit Protection
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Solution Overview
Problem
High electron mobility transistors (HEMTs) are prone to self-destruction due to high current flow, and existing protection devices either reduce blocking voltage, increase on-state resistance, or occupy excessive area, necessitating a more effective short circuit protection solution.
Innovation Solution
A current limiting control structure, such as a Schottky-gated HEMT or metal-insulator-semiconductor HEMT, is integrated between the source and gate electrodes of HEMTs to clamp drain current without significantly affecting on-state resistance, thereby preventing short circuit conditions without increasing the device's area or cell pitch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protection device is located between the gate electrode and the drain electrode within the transistor, then the transistor is protected from self-destruction, but the blocking voltage capability of the transistor is lowered
Solution Approach 1:
A separate protection device is introduced as an intermediary element between the HEMT and the rest of the circuit. This protection device includes a gate electrode, drain electrode, and source electrode configured to limit current flow through the HEMT, thereby protecting it from self-destruction while maintaining the HEMT's original blocking voltage capability without requiring modification to the HEMT structure itself
2Reliability
If a resistor is used as a protection device, then the transistor is protected from self-destruction, but the on-state resistance increases
Solution Approach 1:
The protection device utilizes controlled changes in electrical parameters (voltage and current) to provide protection. By configuring the gate electrode, drain electrode, and source electrode to create voltage-dependent current limiting, the device provides protection only when needed (during overcurrent conditions) while maintaining low on-state resistance during normal operation
3Reliability
If multiple components are used as protection devices, then the transistor is protected from self-destruction, but the area occupied and source resistance increase
Solution Approach 1:
The protection function is merged into a single integrated device structure comprising a gate electrode, drain electrode, and source electrode. This unified structure combines the protection functionality that would otherwise require multiple separate components, thereby reducing the total area occupied and minimizing additional source resistance while maintaining effective protection against HEMT self-destruction
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 current limiting control structure effectively prevents HEMT self-destruction by limiting current flow while maintaining low on-state resistance, thus enhancing the reliability of high electron mobility transistors without the adverse effects of traditional protection devices.
Implementation Method 1
A current limiting control structure, such as a Schottky-gated HEMT or metal-insulator-semiconductor HEMT, is integrated between the source and gate electrodes of HEMTs to clamp drain current
Data Source
AI summary
An electronic device can include a drain electrode of a high electron mobility transistor overlying a channel layer; a source electrode overlying the channel layer, wherein a lowermost portion of the source electrode overlies at least a portion of the channel layer; and a gate electrode of the high electron mobility transistor overlying the channel layer; and a current limiting control structure that controls current passing between the drain and source electrodes. The current limiting control structure can be disposed between the source and gate electrodes, the current limiting control structure can be coupled to the source electrode and the first high electron mobility transistor, and the current limiting control structure has a threshold voltage. The current limiting control structure can be a Schottky-gated HEMT or a MISHEMT.