Ion implantation effects on the characteristics of β-Ga₂O₃ epilayers grown on sapphire by MOCVD

In this study, the Si-ions implantation technique with different doses from 1 × 10¹⁴ to 1 × 10¹⁵ cm⁻² and dose energy 30, 40 and 50 keV was used to tune the electrical properties in unintentionally doped (UID) β-Ga₂O₃ epilayers grown on the sapphire substrates by metalorganic chemical vapor deposition (MOCVD). A high quality UID β-Ga₂O₃ epilayers were fabricated using the optimized growth parameters of MOCVD. The UID and Si-ions implanted β-Ga₂O₃ epilayers were examined and results were compared with the help of X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. Si-ions implantation parameters were also simulated by stopping and range of ions in matter software (SRIM) and actual Si-ions concentration was measured by secondary ions mass spectroscopy. The electrical properties of the implanted β-Ga₂O₃ epilayers were measured by transmission length method and Hall measurements. The sheet resistivity for the β-Ga₂O₃epilayers with Si-ion dose of 1 × 10¹⁴, 6 × 10¹⁴ and 1 × 10¹⁵ cm⁻² were found as 2.047, 0.158 and 0.144 Ω cm, respectively measured by Hall measurements and the electron carrier concentrations for the above doses were 4.39 × 10¹⁸, 6.86 × 10¹⁸ and 7.98 × 10¹⁹ cm⁻³. From the above results, the ion implantation was demonstrated to effectively reduce the resistivity with the high carrier concentrations.