Journal ArticleSilicon-doped β-Ga2O3 films grown at 1 µm/h by suboxide molecular-beam epitaxyAzizie, Kathy; . Hensling, Felix V.; Gorsak, Cameron A.; Kim, Yunjo; Pieczulewski, Naomi A.; Dryden, Daniel M.; Senevirathna, M. K.; Coye, Selena; Shang, Shun-Li; Steele, Jacob; Vogt, Patrick; Parker, Nicholas A.; Birkhölzer, Yorick A.; . McCandless, Jonathan P; Jena, Debdeep; Xing, Huili G.; Liu, Zi-Kui; Williams, Michael D.; Green, Andrew J.; Chabak, Kelson; Muller, David A.; Neal, Adam T.; Mou, Shin; Thompson, Michael O.; Nair, Hari P.; Schlom, Darrell G.We report the use of suboxide molecular-beam epitaxy (S-MBE) to grow β-Ga2O3 at a growth rate of ∼1 μm/h with control of the silicon doping concentration from 5 × 1016 to 1019 cm−3 . In S-MBE, pre-oxidized gallium in the form of a molecular beam that is 99.98% Ga2O, i.e., gallium suboxide, is supplied. Directly supplying Ga2O to the growth surface bypasses the rate-limiting frst step of the two-step reaction mechanism involved in the growth of β-Ga2O3 by conventional MBE. As a result, a growth rate of ∼1 μm/h is readily achieved at a relatively low growth temperature (Tsub ≈ 525 ○C), resulting in flms with high structural perfection and smooth surfaces (rms roughness of <2 nm on ∼1 μm thick flms). Silicon-containing oxide sources (SiO and SiO2) producing an SiO suboxide molecular beam are used to dope the β-Ga2O3 layers. Temperature-dependent Hall effect measurements on a 1 μm thick flm with a mobile carrier concentration of 2.7 × 1017 cm−3 reveal a room-temperature mobility of 124 cm2 V−1 s −1 that increases to 627 cm2 V −1 s−1 at 76 K; the silicon dopants are found to exhibit an activation energy of 27 meV. We also demonstrate working metal–semiconductor feld-effect transistors made from these silicon-doped β-Ga2O3 flms grown by S-MBE at growth rates of ∼1 μm/h.2023-04-0110423986APL materials110411022166-532Xhttps://doi.org/10.1063/5.01396222122147National Science Foundation