Design and simulation of high-breakdown-voltage GaN-based vertical field-effect transistor with interfacial charge engineering

Abstract

A high-breakdown-voltage GaN-based vertical field-effect transistor with negative fixed interfacial charge engineering (GaN ICE-VHFET) is proposed in this work. The negative charge inverts an n-GaN buffer layer along the oxide/GaN interface, inducing a vertical hole layer. Thus, the entire buffer layer consists of a p+-hole inversion layer and an n-pillar buffer layer, and the p-pillar laterally depletes the n-GaN buffer layer, and the electric field distribution becomes more uniform. Simulation results show that the breakdown voltage of the GaN ICE-VHFET increases by 193% and the on-resistance of such a device is still very low when compared with those of conventional vertical FETs. Its figure of merit even exceeds the GaN one-dimensional limit.

The impact of a recessed Δ-shaped gate in a vertical CAVET AlGaN/GaN MIS-HEMT for high-power low-loss switching applications

“…Earlier, vertical HEMTs were criticized because of fabrication difficulties due to the nature and complex structure of the current blocking layer (CBL) [9,10]. However, recent work by many researchers has demonstrated that vertical HEMT structures can be fabricated successfully by adopting techniques such as metalorganic chemical vapor deposition (MOCVD), ion implantation, and molecular beam epitaxy (MBE) to regrow the structure [11,12]. The most widely adopted and prominent gate structures in any vertical devices are the current-aperture vertical electron transistor (CAVET) and the vertical-trench MOSFET [7][8][9][10][11].…”

“…CAVET devices generally operate in depletion mode, but in terms of switching speed and safety, the enhancement mode (E-mode) is a better option for high-power devices [10]. Therefore, techniques such as the cascade CAVET structure [10,11], current blocking layer engineering [10,12], the use of a field plate [6], and recessed gate methods [1] have been adopted in HEMT structures to achieve E-mode operation.…”