Silicon-doped β-Ga2O3 films grown at 1 µm/h by suboxide molecular-beam epitaxy
Source abstract
Abstract
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 first 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 films with high structural perfection and smooth surfaces (rms roughness of <2 nm on ∼1 µm thick films). 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 film 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 field-effect transistors made from these silicon-doped β-Ga2O3 films grown by S-MBE at growth rates of ∼1 µm/h.
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Research context
OpenAlex topics: Ga2O3 and related materials · ZnO doping and properties · Advanced Photocatalysis Techniques
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
Affiliations
Department of Materials Science and Engineering, Cornell University 1 , Ithaca, New York 14853, USA
Air Force Research Laboratory, Materials and Manufacturing Directorate 2 , Wright Patterson Air Force Base, Ohio 45433, USA
Air Force Research Laboratory, Sensors Directorate 3 , Wright Patterson Air Force Base, Ohio 45433, USA
Department of Physics, Clark Atlanta University 4 , Atlanta, Georgia 30314, USA
Department of Material Science and Engineering, Pennsylvania State University 5 , University Park, Pennsylvania 16802, USA
School of Electrical and Computer Engineering, Cornell University 6 , Ithaca, New York 14853, USA
Kavli Institute at Cornell for Nanoscale Science 7 , Ithaca, New York 14853, USA
School of Applied and Engineering Physics, Cornell University 8 , Ithaca, New York 14853, USA
Leibniz-Institut für Kristallzüchtung 9 , Max-Born-Str. 2, 12489 Berlin, Germany
Funding
Air Force Office of Scientific Research · National Science Foundation · Office of Naval Research · Semiconductor Research Corporation · Defense Advanced Research Projects Agency · Alexander von Humboldt-Stiftung
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