title: Optimization of ion-atomic beam source for deposition of GaN ultrathin films.
abstract: We describe the optimization and application of an ion-atomic beam source for ion-beam-assisted deposition of ultrathin films in ultrahigh vacuum. The device combines an effusion cell and electron-impact ion beam source to produce ultra-low energy (20-200 eV) ion beams and thermal atomic beams simultaneously. The source was equipped with a focusing system of electrostatic electrodes increasing the maximum nitrogen ion current density in the beam of a diameter of ≈15 mm by one order of magnitude (j ≈ 1000 nA/cm(2)). Hence, a successful growth of GaN ultrathin films on Si(111) 7 × 7 substrate surfaces at reasonable times and temperatures significantly lower (RT, 300 °C) than in conventional metalorganic chemical vapor deposition technologies (≈1000 °C) was achieved. The chemical composition of these films was characterized in situ by X-ray Photoelectron Spectroscopy and morphology ex situ using Scanning Electron Microscopy. It has been shown that the morphology of GaN layers strongly depends on the relative Ga-N bond concentration in the layers.
authors.affiliation: Institute of Physical Engineering, Brno University of Technology, Technická 2, 616 69 Brno, Czech Republic.
authors.forename: Jindřich
authors.initials: J
authors.lastname: Mach
authors.affiliation: Institute of Physical Engineering, Brno University of Technology, Technická 2, 616 69 Brno, Czech Republic.
authors.forename: Tomáš
authors.initials: T
authors.lastname: Šamořil
authors.affiliation: Institute of Physical Engineering, Brno University of Technology, Technická 2, 616 69 Brno, Czech Republic.
authors.forename: Miroslav
authors.initials: M
authors.lastname: Kolíbal
authors.affiliation: Institute of Physical Engineering, Brno University of Technology, Technická 2, 616 69 Brno, Czech Republic.
authors.forename: Jakub
authors.initials: J
authors.lastname: Zlámal
authors.affiliation: Institute of Physical Engineering, Brno University of Technology, Technická 2, 616 69 Brno, Czech Republic.
authors.forename: Stanislav
authors.initials: S
authors.lastname: Voborny
authors.affiliation: Institute of Physical Engineering, Brno University of Technology, Technická 2, 616 69 Brno, Czech Republic.
authors.forename: Miroslav
authors.initials: M
authors.lastname: Bartošík
authors.affiliation: Institute of Physical Engineering, Brno University of Technology, Technická 2, 616 69 Brno, Czech Republic.
authors.forename: Tomáš
authors.initials: T
authors.lastname: Šikola