12 W/mm AlGaN–GaN HFETs on Silicon Substrates

TLDR

Al₀.₂₆Ga₀.₇₄N/GaN heterojunction field‑effect transistors were grown by metal‑organic chemical vapor deposition on high‑resistivity 100‑mm Si(111) substrates. The devices exhibit a 2‑D electron gas sheet resistance of 300 Ω/□, a maximum drain current density of ~1 A/mm, a 200‑V breakdown voltage, fT of 18 GHz, fmax of 31 GHz, and deliver 12 W/mm at 2.14 GHz with 15.3 dB gain and 52.7 % power‑added efficiency—setting the highest power density for GaN on silicon and rivaling the best conventional designs.

Abstract

Al/sub 0.26/Ga/sub 0.74/N-GaN heterojunction field-effect transistors were grown by metal-organic chemical vapor deposition on high-resistivity 100-mm Si (111) substrates. Van der Pauw sheet resistance of the two-dimensional electron gas was 300 /spl Omega//square with a standard deviation of 10 /spl Omega//square. Maximum drain current density of /spl sim/1 A/mm was achieved with a three-terminal breakdown voltage of /spl sim/200 V. The cutoff frequency and maximum frequency of oscillation were 18 and 31 GHz, respectively, for 0.7-μm gate-length devices. When biased at 50 V, a 2.14-GHz continuous wave power density of 12 W/mm was achieved with associated large-signal gain of 15.3 dB and a power-added efficiency of 52.7%. This is the highest power density ever reported from a GaN-based device grown on a silicon substrate, and is competitive with the best results obtained from conventional device designs on any substrate.