Design and simulation of T‐gate AlN/β‐Ga₂O₃ HEMT for DC, RF and high‐power nanoelectronics switching applications

Abstract

In this paper, we report DC and RF analysis of a T‐gate AlN/β‐Ga2O3 high electron mobility transistors (HEMTs) by optimizing the gate‐drain distance (LGD) and two T‐gate dimensions given by the—head‐length (LHL) and the foot‐length (LFL). A two‐dimensional (2‐D) physics‐based device simulator attuned with experimental results is used to perform the analysis. The AlN/β‐Ga2O3 HEMT achieves a high two‐dimensional electron gas (2DEG) density of ~3 × 1013 cm−2, which is attributed to large spontaneous as well as piezoelectric polarization components of the 10 nm AlN thick barrier layer. 2DEG density is also numerically validated using widely used polarization model for III nitrides. It is demonstrated that a highly scaled, both lateral and vertical, device with optimized T‐gate dimensions achieves higher blocking voltage (VBR), low on‐resistance (RON), higher cut‐off frequency (fT) and higher maximum oscillation frequency (fMAX), simultaneously. Consequently, AlN/β‐Ga2O3 HEMT achieves a low specific‐on resistance (RON,sp) of 0.1 mΩ cm2 and an off‐state breakdown voltage of 904 V, which corresponds to the record power figure‐of‐merit (PFoM) of ~8172 MW/cm2. Furthermore, fT of 73 GHz and fMAX of 142 GHz are estimated. These results—low power conduction loss along with higher blocking voltage, and superior RF parameters show the potential of the analyzed device T‐gate AlN/β‐Ga2O3 HEMT for high‐power switching and RF applications.

Progress in Gallium Oxide Field-Effect Transistors for High-Power and RF Applications

“…AlN is potentially a better alternative to AlGO/GO MODFETs with its higher CBO to β-Ga 2 O 3 of ≈1.7-1.86 eV and polarization-induced charge, leading to larger 2DEG concentrations of 3 × 10 13 -5 × 10 13 cm −2 [192][193][194]. Currently, no AlN/β-Ga 2 O 3 HEMTs have been fabricated and reported; however, multiple TCAD simulations show promise, with much higher frequency operations up to an f T of 166 GHz and f max of 142 GHz [195][196][197].…”