Performance Analysis of AlN/GaN HEMTs on β-Ga2O3 Through Exploration of Varied Back Barriers: An Investigative Study for Advanced RF Power Applications

• Published in: Journal of electronic materials 2024-07, Vol.53 (7), p.3887-3900
• Main Authors: Venkatesan, R. S., Manickam, Rajeswari, Duraipandi, Brindha, Sugathan, Krishnapriya Kottakkal
• Format: Article
• Language: English
• Subjects: Aluminum gallium nitrides; Aluminum nitride; Barrier layers; Buffers; Characterization and Evaluation of Materials; Charge density; Chemistry and Materials Science; Computer science; Confinement; Current carriers; Design optimization; Electronics and Microelectronics; Electrons; Engineering; Gallium nitrides; Gallium oxides; High electron mobility transistors; Indium; Instrumentation; Leakage current; Materials Science; Optical and Electronic Materials; Original Research Article; Power; Quantum wells; Semiconductor devices; Silicon carbide; Silicon nitride; Silicon substrates; Simulation; Solid State Physics; Transistors; Wafers
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-024-11100-1

Gallium nitride (GaN) high-electron-mobility transistors (HEMTs) on β-gallium oxide (β-Ga 2 O 3 ) wafers with various back barrier (BB) materials have garnered considerable attention, mainly due to the superior sheet charge density achieved by the confinement of a large number of electrons in the quantum well, which improves RF performance even further. This work investigates the role of different BB materials of Fe-doped AlGaN buffer AlN/GaN HEMTs on β-Ga 2 O 3 wafers (substrate) with gate–source ( L GS ) and gate–drain ( L GD ) distances of 0.4 µm and 1.2 µm, respectively. When compared to traditional substrates such as silicon carbide and silicon, a β-Ga 2 O 3 substrate is more affordable, is accessible in large wafer sizes, and has a lower lattice mismatch (0.4–2.4%) with AlGaN alloys. The effects of gate length scaling (Lg = 50 nm, 100 nm, and 150 nm) on the proposed HEMT devices were also analysed. The short-channel effects can be mitigated by introducing BB structures, which helps avoid further scaling of the barrier layer. With a p-diamond BB of 100 nm thickness, an Fe-doped AlGaN buffer rectangular gated AlN/GaN HEMT Lg = 50 nm results in maximum I D of 5.23 A/mm, g m of 1723 mS/mm, and f T of 361.6 GHz. This superior DC/RF performance can be achieved due to the large confinement of charge carriers into the quantum well and the low leakage current achieved by introducing BB structures and Fe-doped AlGaN buffer. With this outstanding performance, the proposed HEMT device is a promising candidate for next-generation RF applications.