Two-dimensional electron gas isolation mechanism in Al0.2Ga0.8N/GaN heterostructure by low-energy Ar, C, Fe ion implantation

• Published in: Applied surface science 2024-11, Vol.674, p.160885, Article 160885
• Main Authors: Scandurra, Antonino, Ragonese, Paolo, Calabretta, Cristiano, Zahra, Khadisha, Soomary, Liam, Roccaforte, Fabrizio, Greco, Giuseppe, Piluso, Nicolò, Eloisa Castagna, Maria, Iucolano, Ferdinando, Severino, Andrea, Bruno, Elena, Mirabella, Salvo
• Format: Article
• Language: English
• Subjects: Argon; Carbon; HEMT; Ion implantation; Iron; Two-dimensional electron gas
• ISSN: 0169-4332
• DOI: 10.1016/j.apsusc.2024.160885

[Display omitted] •Ar, C, and Fe low energy and low fluence Ion implantation for 2DEG electrical isolation.•Defects creation by ion implantation in AlGaN/GaN heterostructure.•2DEG AlGaN/GaN high electron mobility transistor (HEMT).•Non-radiative recombination centers produced by Ion bombardment.•High thermal stability of 2DEG isolation by ion implantation.•Defects diffusion towards AlGaN surface. We report a comparative study of the isolation mechanisms of two-dimensional electron gas (2-DEG) in Al0.2Ga0.8N/GaN heterostructure by room temperature ion implantation with Ar, C or Fe at 15, 20, 18 keV and fluences of 7 × 1013, 1 × 1014, 5 × 1013 cm−2, respectively. The samples were annealed up to 900 °C post-implantation and characterized by X-ray Diffraction, X-ray Photoelectron Spectroscopy, Photoluminescence, Rutherford Backscattering Spectrometry in Channeling mode and Capacitance Voltage profiling. The ion implantation produces unrecoverable crystal lattice damage such as point defects and non-radiative carrier traps level into the band gap of GaN. As a consequence, a decrease in the number of occupied states at the upper side of the valence band of GaN was observed. Moreover, defects accumulation at the near-surface region by annealing at 900 °C was observed. Due to the various defects, the concentration of 2-DEG carriers, after ion implantation, for all three ions investigated, is reduced from 1019-1020 to less than 1013 ––1014 cm−3. The 2-DEG isolation was stable up to 900 °C for all three ions, while the non-radiative defects and carrier traps produced were slightly more stable in the case of Fe implantation. The reduction of carrier concentration is responsible for the isolation of 2-DEG.