Performance Enhancement of AlGaN/GaN HEMT using Field Plates

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Name of the Speaker: Ms. Aishwarya Kaity (EE20D013)
Guide: Dr. Nandita DasGupta
Venue: CSD-308
Date/Time: 15th September 2023 (Friday), 3:00 PM

GaN-based High Electron Mobility Transistor (HEMT) stands out for its power density due to high carrier density and polarization effects. AlGaN/GaN HEMTs exhibit improved electron mobility, making them suitable for high-frequency and high-temperature applications. GaN-based HEMTs offer advantages like low switching loss and high switching speed. These devices find use in RF and millimeter-wave applications due to their shorter gate length and GaN’s integration benefits.

To enhance breakdown performance, technologies like Gate Field Plate (GFP), Source Field Plate (SFP), and Drain Field Plate (DFP) are explored. GFP redistributes the electric field, improving breakdown performance. However, GFPs increase parasitic capacitance. Multiple GFPs enhance breakdown voltage but complicate fabrication. SFPs connected to the source improve power performance but may reduce cut-off frequency due to increased gate-to-source parasitic capacitance.

A new approach is presented here which introduces an SFP that doesn’t overlap with Gate and gate-to-source access region. This 3D design avoids parasitic capacitance increase and simplifies fabrication. Simulation results demonstrate increased breakdown voltage and improved cut-off frequency due to optimized field plate dimensions.

The simulation work evaluates AlGaN/GaN HEMTs with various field plate structures. The proposed non-overlapping source field plate design showcases 150% breakdown voltage increase, 72% reduction in parasitic capacitance, and 74% cut-off frequency improvement compared to conventional HEMTs. This device exhibits high-power capability, swift switching, and cost-effectiveness.