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

• Published in: IEEE microwave and wireless technology letters (Print) 2023-06, Vol.33 (6), p.839-842
• Main Authors: Howell, Robert S., Novak, Brian, Vasen, Timothy, Shea, Patrick, Chang, Josephine, Afroz, Shamima
• Format: Article
• Language: English
• Subjects: Aluminum gallium nitrides; Amplification; Amplifiers; Carrier density; Current carriers; Field effect transistors; Gallium nitrides; Heterostructures; Nanoribbons; Semiconductor devices; Superlattices; Topology
• ISSN: 2771-957X; 2771-9588
• 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 [Formula Omitted]-band systems, leveraging the high carrier density and a high degree of charge control offered by this device topology for mmW and [Formula Omitted]-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 [Formula Omitted] 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 [Formula Omitted]–[Formula Omitted] at