A Novel Isolation Approach for GaN-Based Power Integrated Devices.

Area of Science:

• Materials Science
• Electrical Engineering
• Semiconductor Physics

Background:

• Monolithic integration of Gallium Nitride (GaN)-based vertical and lateral devices presents unique challenges.
• Driving high-power vertical GaN switching devices using lateral GaN High Electron Mobility Transistors (HEMTs) requires minimal losses and enhanced stability.
• Ensuring effective electrical isolation between these integrated devices is critical for performance.

Purpose of the Study:

• To introduce a novel technology for monolithic integration of GaN-based vertical and lateral devices.
• To propose and validate a new method for electrical isolation between vertical GaN power FinFETs and lateral GaN HEMTs.
• To prevent performance degradation of the lateral GaN HEMT due to high voltage applied to the vertical device.

Main Methods:

• Development of a novel isolation strategy using a highly doped n+ GaN layer.
• Positioning the n+ GaN layer between the epitaxial layers of the vertical and lateral GaN devices.
• Validation of the isolation method using TCAD-Sentaurus device simulation.

Main Results:

• The proposed n+ GaN isolation layer effectively blocks the vertical electric field.
• The isolation method prevents depletion or enhancement of the 2D electron gas (2DEG) in the lateral GaN HEMT.
• Demonstrated prevention of threshold voltage shift and maintained device stability and driver performance.

Conclusions:

• The novel n+ GaN isolation strategy enables successful monolithic integration of vertical and lateral GaN devices.
• This approach overcomes a significant challenge in GaN device integration, enhancing stability and performance.
• This work represents a pioneering publication in isolation strategies for combined vertical and lateral GaN devices.