AVS 53rd International Symposium
    Applied Surface Science Thursday Sessions
       Session AS-ThP

Paper AS-ThP18
Epitaxial Growth of NbN and MgO Films for Superconducting Single Photon Detectors and Josephson Junction Qubits

Thursday, November 16, 2006, 5:30 pm, Room 3rd Floor Lobby

Session: Aspects of Applied Surface Science Poster Session
Presenter: J.S. Kline, National Institute of Standards and Technology
Authors: J.S. Kline, National Institute of Standards and Technology
S. Oh, National Institute of Standards and Technology
R.H. Hadfield, National Institute of Standards and Technology
A. Lita, National Institute of Standards and Technology
S.W. Nam, National Institute of Standards and Technology
D.P. Pappas, National Institute of Standards and Technology
Correspondent: Click to Email
The growth of ultrathin epitaxial aluminum oxide tunnel barriers on Re has been proven to reduce the number of spurious resonators in Josephson phase qubits when compared to qubits fabricated with amorphous tunnel barriers. Other epitaxial tunnel barrier materials such as MgO may also improve device performance. The superconductor NbN is latticed matched to MgO and was studied in this work. The NbN/MgO material system is also well suited for superconducting single photon detectors and NbN thin films were grown for this purpose. Niobium nitride films were deposited on MgO substrates by UHV reactive sputtering in an argon/nitrogen gas mixture. Magnesium oxide tunnel barriers were deposited by RF sputtering and also by reactive evaporation of magnesium in a controlled oxygen background. To achieve epitaxy, the substrate was held at elevated temperature during the deposition. Surface science tools such as Auger electron spectroscopy, scanning tunneling microscopy, and reflection high energy electron diffraction were used for in-situ analysis of the grown films.