Filters

20232

More filters

20232
Reset filters

Settings

End date: 2024 × Start date: 2020 × DDC: 530 × Publisher: Melville, NY : American Inst. of Physics × WGL Institute: IKZ ×

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Suppression of particle formation by gas-phase pre-reactions in (100) MOVPE-grown β -Ga2O3films for vertical device application
    (Melville, NY : American Inst. of Physics, 2023) Chou, Ta-Shun; Seyidov, Palvan; Bin Anooz, Saud; Grüneberg, Raimund; Pietsch, Mike; Rehm, Jana; Tran, Thi Thuy Vi; Tetzner, Kornelius; Galazka, Zbigniew; Albrecht, Martin; Irmscher, Klaus; Fiedler, Andreas; Popp, Andreas
    This work investigated the metalorganic vapor-phase epitaxy (MOVPE) of (100) β-Ga2O3 films with the aim of meeting the requirements to act as drift layers for high-power electronic devices. A height-adjustable showerhead achieving a close distance to the susceptor (1.5 cm) was demonstrated to be a critical factor in increasing the stability of the Ga wetting layer (or Ga adlayer) on the surface and reducing parasitic particles. A film thickness of up to 3 μm has been achieved while keeping the root mean square below 0.7 nm. Record carrier mobilities of 155 cm2 V-1 s-1 (2.2 μm) and 163 cm2 V-1 s-1 (3 μm) at room temperature were measured for (100) β-Ga2O3 films with carrier concentrations of 5.7 × 1016 and 7.1 × 1016 cm-3, respectively. Analysis of temperature-dependent Hall mobility and carrier concentration data revealed a low background compensating acceptor concentration of 4 × 1015 cm-3.
  • Thumbnail Image
    Item
    Bulk single crystals and physical properties of β-(AlxGa1-x)2O3(x = 0-0.35) grown by the Czochralski method
    (Melville, NY : American Inst. of Physics, 2023) Galazka, Zbigniew; Fiedler, Andreas; Popp, Andreas; Ganschow, Steffen; Kwasniewski, Albert; Seyidov, Palvan; Pietsch, Mike; Dittmar, Andrea; Anooz, Saud Bin; Irmscher, Klaus; Suendermann, Manuela; Klimm, Detlef; Chou, Ta-Shun; Rehm, Jana; Schroeder, Thomas; Bickermann, Matthias
    We have systematically studied the growth, by the Czochralski method, and basic physical properties of a 2 cm and 2 in. diameter bulk β-(AlxGa1-x)2O3 single crystal with [Al] = 0-35 mol. % in the melt in 5 mol. % steps. The segregation coefficient of Al in the Ga2O3 melt of 1.1-1.2 results in a higher Al content in the crystals than in the melt. The crystals were also co-doped with Si or Mg. [Al] = 30 mol. % in the melt (33-36 mol. % in the crystals) seems to be a limit for obtaining bulk single crystals of high structural quality suitable for homoepitaxy. The crystals were either semiconducting (no intentional co-dopants with [Al] = 0-30 mol. % and Si-doped with [Al] = 15-20 mol. %), degenerately semiconducting (Si-doped with [Al] ≤ 15 mol. %), or semi-insulating ([Al] ≥ 25 mol. % and/or Mg-doped). The full width at half maximum of the rocking curve was 30-50 arcsec. The crystals showed a linear but anisotropic decrease in all lattice constants and a linear increase in the optical bandgap (5.6 eV for [Al] = 30 mol. %). The room temperature electron mobility at similar free electron concentrations gradually decreases with [Al], presumably due to enhanced scattering at phonons as the result of a larger lattice distortion. In Si co-doped crystals, the scattering is enhanced by ionized impurities. Measured electron mobilities and bandgaps enabled to estimate the Baliga figure of merit for electronic devices.