GaN SLCFET Technology for Next Generation mmW Systems, Demonstrating P} of 10.87 W/mm With 43% PAE at 94 GHz

• Published in: IEEE microwave and wireless technology letters (Print) 2023-05, p.1-4
• Main Authors: Howell, Robert S., Novak, Brian, Vasen, Timothy, Shea, Patrick, Chang, Josephine, Afroz, Shamima
• Format: Article
• Language: English
• Subjects: <inline-formula xmlns:ali="http://www.niso.org/schemas/ali/1.0/" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <tex-math notation="LaTeX"> W</tex-math> </inline-formula>-band; Density measurement; Gallium nitride; Gallium nitride (GaN); HEMTs; Logic gates; millimeter wave devices; MMIC; Nanoribbons; Performance evaluation; power amplifiers; Power system measurements; superlattice
• ISSN: 2771-957X
• DOI: 10.1109/LMWT.2023.3271862

We report on the development of the super-lattice castellated field effect transistor (SLCFET) technology as a candidate for the next generation of mmW and W -band systems, leveraging the high carrier density and a high degree of charge control offered by this device topology for mmW and W -band power amplification. The SLCFET is built using a superlattice of stacked AlGaN/gallium nitride (GaN) heterostructures that are etched into nanoribbons between epitaxial regrown n + GaN source and drain contacts and controlled with a 100 nm length T-gate that electrostatically actuates the stacked channels from the sidewalls. The 2 \times 20 \mu m amplifier cells of SLCFET devices were measured using load-pull at 94 GHz using a 12-V bias, demonstrating amplifier output power densities of 10.87 W/mm with 43% power added efficiency (PAE) at peak power and a maximum linear gain of 5.4 dB. The SLCFET amplifier process attains this power density due to its extremely high current density, with an IMAX of 4.8 A/mm, along with its minimal dispersion, with current collapse measured using pulsed I - V at