Analysis of Operational Characteristics of AlGaN/GaN High-Electron-Mobility Transistor with Various Slant-Gate-Based Structures: A Simulation Study

Abstract

This study investigates the operational characteristics of AlGaN/GaN high-electron-mobility transistors (HEMTs) by applying a slant-gate structure and drain-side extended field-plate (FP) for improved breakdown voltage. Prior to the analysis of slant-gate-based HEMT, simulation parameters were extracted from the measured data of fabricated basic T-gate HEMTs to secure the reliability of the results. We suggest three different types of slant-gate structures that connect the basic T-gate electrode boundary to the 1st and 2nd SiN passivation layers obliquely. To consider both the breakdown voltage and frequency characteristics, the DC and RF characteristics of various slant-gate structures including the self-heating effect were analyzed by TCAD simulation. We then applied a drain-side extended FP to further increase the breakdown voltage. The maximum breakdown voltage was achieved at the FP length of 0.4 μm. Finally, we conclude that the slant-gate structures can improve breakdown voltage by up to 66% without compromising the frequency characteristics of the HEMT. When the drain-side FP is applied to a slant-gate structure, the breakdown voltage is further improved by up to 108%, but the frequency characteristics deteriorate. Therefore, AlGaN/GaN HEMTs with an optimized slant-gate-based structure can ultimately be a promising candidate for high-power and high-frequency applications.

Barrier and channel thickness engineering to optimize fin height for enhancement mode Al0.3Ga0.7N/GaN FinHEMT

“…The maximum 2DEG depletion is observed, i.e., electron concentration from 10 19 cm −3 to 10 18 cm −3 (as shown in the inset of Figure 9) for the full tri‐gate design style. This depletion can be justified due to the full tri‐gate electrostatics on the 2DEG near the interface 26 . Thus, the tri gate FinHEMT structure is one of viable emerging gate design approach to deplete 2DEG from the hetero interface, and thus the AlGaN/GaN FinHEMT structure can be made suitable for E‐mode of operation in power electronics and high frequency switching applications 27,28 …”

“…This depletion can be justified due to the full tri-gate electrostatics on the 2DEG near the interface. 26 Thus, the tri gate FinHEMT structure is one of viable emerging gate design approach to deplete 2DEG from the hetero interface, and thus the AlGaN/GaN FinHEMT structure can be made suitable for E-mode of operation in power electronics and high frequency switching applications. 27,28 Further, to confirm our stand on the full tri-gate influence on 2DEG, electrostatic simulations were carried out on the un-optimized Al 0.3 Ga 0.7 N/GaN FinHEMT structure as depicted in Figure 1B for clear visibility of shifting of conduction band energy level.…”

Optimization of Gate-Head-Top/Bottom Lengths of AlGaN/GaN High-Electron-Mobility Transistors with a Gate-Recessed Structure for High-Power Operations: A Simulation Study

“…The peak concentration of acceptor trap doping was , which decreased gradually following a Gaussian doping profile [ 20 ]. The acceptor doping concentration in the AlGaN/GaN interface region was set to based on values reported in a previous study [ 21 ].…”

“…Subsequently, the accumulated electrons in the AlGaN layer flow into the GaN layer and become confined until the Fermi levels of AlGaN and GaN become equal, thereby forming the 2-DEG. Therefore, the 2-DEG with a density of is formed in the heterojunction interface between AlGaN and GaN [ 21 ].…”

Enhanced Operational Characteristics Attained by Applying HfO2 as Passivation in AlGaN/GaN High-Electron-Mobility Transistors: A Simulation Study

“…In order to conduct an accurate device simulation by considering the self-heating effect (SHE), we applied physical models to calculate the heat generation within the device [ 22 , 23 ]. First, we used the lattice heat flow equation, where is the heat capacitance per unit volume, is the thermal conductivity coefficient, is the heat generation, and is the local lattice temperature.…”