Semi-floating-gate GaN HEMT with Diode and Capacitor
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Solution Overview
Problem
The existing gallium nitride high-electron-mobility power devices face challenges in being manufactured as normally off type devices, leading to complex structures and low reliability when used in power switches, particularly due to issues like dynamic avalanche and breakdown in common-source and common-gate configurations.
Innovation Solution
A semi-floating-gate power device is introduced, comprising a gallium nitride high-electron-mobility transistor with a diode connecting the gate to the source or channel area and a capacitor connected to an external voltage signal, simplifying the structure and enhancing reliability through capacitive coupling and diode clamping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a common-source and common-gate gallium nitride power switch is used, then the device can be manufactured with existing gate drivers, but the structure becomes complicated and reliability decreases
Solution Approach 1:
The patent merges the normally-on gallium nitride transistor and normally-off silicon MOS transistor into a single integrated device structure. The silicon MOS transistor is formed within the gallium nitride semiconductor layer, creating a unified device that combines both transistor types' functions while eliminating the need for separate external connections and reducing overall structural complexity.
Solution Approach 2:
The integrated device serves multiple functions simultaneously: the gallium nitride portion provides high-voltage handling and the silicon MOS portion provides threshold voltage control. This multi-functional design allows the single device to replace what previously required two separate transistors connected in parallel, simplifying the overall system architecture.
2Ease of manufacture
If a common-source and common-gate gallium nitride power switch is used, then the device can be manufactured with existing gate drivers, but reliability decreases due to dynamic avalanche and breakdown issues
Solution Approach 1:
The patent introduces an intermediate silicon MOS transistor structure that mediates between the gallium nitride channel and the external circuit. This intermediate layer provides controlled coupling and isolation, preventing direct exposure to harmful electrical transients and improving overall device reliability during dynamic operation.
3Ease of operation
If a normally off gallium nitride transistor is manufactured, then the device can turn off completely, but the threshold voltage is close to 0V and the device is easily opened by mistake
Solution Approach 1:
The patent uses a composite structure combining gallium nitride and silicon materials. The silicon MOS transistor portion provides a controllable threshold voltage characteristic that differs from pure gallium nitride devices, enabling better control over the off-state and preventing false activation while maintaining the ability to turn off completely when needed.
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 semi-floating-gate power device simplifies the gallium nitride power device structure, improves reliability by allowing high-voltage and high-speed operation, and increases the threshold voltage of the gallium nitride transistor, enabling it to function effectively as a power switch.
Implementation Method 1
a capacitor whose one end is connected with the gate of the gallium nitride high-electron-mobility transistor and whose other end is connected with an external voltage signal
Implementation Method 2
A diode whose anode is connected with the gate of the gallium nitride high-electron-mobility transistor and whose cathode is connected with the source or the channel area of the gallium nitride high-electron-mobility transistor
Data Source
AI summary
The disclosure belongs to the technical field of semiconductor power devices, specifically relates to a semi-floating-gate power device, and comprises the gallium nitride high-electron-mobility transistor, the diode and the capacitor; the anode of the diode is connected with the gate of the gallium nitride high-electron-mobility transistor and the cathode of the diode is connected with the source or the channel area of the gallium nitride high-electron-mobility transistor; one end of the capacitor is connected with the gate of the gallium nitride high-electron-mobility transistor and the other end of the capacitor is connected with the external voltage signal. The semi-floating-gate power device has a simple structure, is easy to manufacture, adapts to high-voltage and high-speed operation and has very high reliability, can increase the threshold voltage of the gallium nitride high-electron-mobility transistor in the working state, so that the transistor can serve as the power switch tube better.