2 W mm⁻¹ power density of an AlGaN/GaN HEMT grown on free-standing GaN substrate at 40 GHz

Abstract

In this letter, a record performance at 40 GHz obtained on an AlGaN/GaN high electron mobility transistor (HEMT) grown on hydride vapor phase epitaxy free-standing GaN substrate is reported. An output power density of 2 W mm −1 associated with 20.5% power added efficiency and a linear power gain (G p ) of 4.2 dB is demonstrated for 70 nm gate length device. The device exhibits a maximum DC drain current density of 950 mA mm −1 and a peak extrinsic transconductance (g m Max ) of 300 mS mm −1 at V DS =6 V. A 100 GHz maximum intrinsic cutoff frequency f T , and a maximum intrinsic oscillation frequency f Max of 125 GHz are obtained from S-parameters measurement. This performance is very promising for HEMTs grown on freestanding GaN substrate.

Performance improvement with non-alloyed ohmic contacts technology on AlGaN/GaN High Electron Mobility Transistors on 6H-SiC substrate

“…On 10 x 10 µm 2 area scan, the RMS roughness is 0.7 nm. For comparison purposes, HEMTs are also fabricated on the same heterostructure with standard process [8] with Ti/Al/Ni/Au ohmic contacts requiring rapid thermal annealing at high temperature.…”

“…No annealing is required. The rest of the HEMT fabrication is unchanged from the standard process used at IEMN [8]. Devices isolation is performed by N + ion multiple implantations.…”

Cathodoluminescence and electrical study of vertical GaN-on-GaN Schottky diodes with dislocation clusters

“…For this study, 3 µm thick GaN films were grown on three 2-inch HVPE GaN substrates by MOVPE in a close-coupled showerhead Aixtron reactor. [22] Ammonia, trimethylgallium, and hydrogen carrier gas were used to grow the films at 1020 °C with a growth rate of 2 µm.h -1 .…”

Hot-wall MOCVD of N-polar group-III nitride materials

“…In addition, the dislocation density in layers grown on sapphire (10 8 cm −2 ) [38,39] and Si (10 9 cm −2 ) SECTION 1.2. Fundamental properties of group-III nitride semiconductors 3 [ [40][41][42] is usually higher in comparison to material grown on SiC [42,43]. Dislocations typically present leakage current paths limiting device performance.…”