GaN FinFETs and trigate devices for power and RF applications: review and perspective

Abstract

Gallium nitride (GaN) is becoming a mainstream semiconductor for power and radio-frequency (RF) applications. While commercial GaN devices are increasingly being adopted in data centers, electric vehicles, consumer electronics, telecom and defense applications, their performance is still far from the intrinsic GaN limit. In the last few years, the fin field-effect transistor (FinFET) and trigate architectures have been leveraged to develop a new generation of GaN power and RF devices, which have continuously advanced the state-of-the-art in the area of microwave and power electronics. Very different from Si digital FinFET devices, GaN FinFETs have allowed for numerous structural innovations based on engineering the two-dimensional-electron gas or p–n junctions, in both lateral and vertical architectures. The superior gate controllability in these fin-based GaN devices has not only allowed higher current on/off ratio, steeper threshold swing, and suppression of short-channel effects, but also enhancement-mode operation, on-resistance reduction, current collapse alleviation, linearity improvement, higher operating frequency, and enhanced thermal management. Several GaN FinFET and trigate device technologies are close to commercialization. This review paper presents a global overview of the reported GaN FinFET and trigate device technologies for RF and power applications, as well as provides in-depth analyses correlating device design parameters to device performance space. The paper concludes with a summary of current challenges and exciting research opportunities in this very dynamic research field.

Enhancement-Mode Multi-Channel AlGaN/GaN Transistors With LiNiO Junction Tri-Gate

“…P-type LiNiO junction gate resulted in an over 0.5 V shift in V TH compared with the most positive V TH achieved on MOS multi-channel tri-gate structures with the same W Fin . The maximum V TH achieved on LiNiO multichannel devices was 1.2 V (for W Fin of 15 nm and L Fin of 1.5 μm), which is very close to the theoretical prediction for e-mode tri-gate device [18]. While long-fin devices were fabricated to explore the maximum possible V TH of proposed structure, a better balance between the V TH and on-state performance was achieved for a device with L Fin of 1 μm, which was chosen for the further characterizations.…”

(Invited) How to Achieve Low Thermal Resistance and High Electrothermal Ruggedness in Ga2O3 Devices?

“…1(c) and (d) show the forward I-V and highbias reverse I-V characteristics of the fabricated Ga2O3 SBDs, respectively, demonstrating the capability of blocking at least 500 V up to 600 K. The high-bias leakage current can be explained by a combination of the thermionic-field emission (TFE) across the Schottky barrier and the electron hopping via the defect states in the depletion region (18). The latter mechanism was widely reported in other wide-bandgap high-voltage power devices, e.g., GaN (23)(24)(25)(26)(27) and SiC (28)(29)(30). These results verify the high-temperature stability of high-voltage Ga2O3 SBDs.…”

Structural Analysis of Low Defect Ammonothermally Grown GaN Wafers by Borrmann Effect X-ray Topography

“…Gallium nitride (GaN) wafers of the highest structural quality are needed for building optoelectronic and electronic device structures. These include laser diodes (LDs) as well as vertical field-effect transistors (FETs) and high electron mobility transistors (HEMTs) [ 1 , 2 , 3 ]. In order to prepare GaN wafers, bulk crystals have to be grown.…”