High-Efficiency Doping Outcomes in Homoepitaxial β-Ga2O3 Films via Pulsed Si Doping with MOCVD

Abstract

Using metal–organic chemical vapor deposition, pulsed Si-doped homoepitaxial gallium oxide (β-Ga₂O₃) films were deposited on (010) β-Ga₂O₃ substrates. The impact of the Si pulse duty cycle on the morphology, structure, and electrical properties of the films was investigated. The full width at half-maximum (fwhm) of the (020) rocking curves for all doped films was less than 55 arcsec, indicating high crystal quality. Employing pulse width modulation of Si doping, as opposed to continuous Si doping, has resulted in a reduction in surface roughness by approximately 2.83 to 9.32 times. Notably, under the conditions of a 0.3 min Si source vent time and a 0.1 min run, an activation ratio of up to 99.1% was achieved, maximizing the electrical performance. This included achieving the lowest resistivity of 0.0042 Ω·cm and an electron mobility of 44.1 cm²/(V s) at a carrier concentration of 3.35 × 10¹⁹ cm^–3. The application of pulsed Si doping provided sufficient diffusion time for Si atoms, enabling effective doping and thereby enhancing the high carrier concentration electrical performance of the films, offering an effective pathway for their use as ohmic contacts in ultrawide-bandgap semiconductor devices.