A design-of-experiments statistical approach was taken to determine the optimum ion gun operating parameters for the deposition of moisture-stable, low-absorbing hafnium oxide films by ion-assisted electron-beam evaporation. Factors identified as affecting the quality of hafnia films were chamber pressure, deposition rate, ion gun source gas composition, and ion gun current. Both oxygen and argon were used as source gases. High and low levels of the factors were chosen on the basis of our experience with the operating range of the system, and we made a series of 24 runs with all possible combinations of these factors. From a statistical analysis of the data, we find that the best films are obtained with a 1:1 mixture of argon and oxygen, 3–3.5 × 10<sup>−4</sup> Torr chamber pressure, 0.3-nm/s deposition rate, and 0.5-A ion gun current. X-ray diffraction measurements show that the ion-assisted films exhibit a partial monoclinic crystalline structure, whereas the unassisted films are amorphous.
© 2002 Optical Society of America
(310.0310) Thin films : Thin films
(310.1860) Thin films : Deposition and fabrication
(310.3840) Thin films : Materials and process characterization
(310.6860) Thin films : Thin films, optical properties
Traci R. Jensen, John Warren, and Robert L. Johnson, "Ion-Assisted Deposition of Moisture-Stable Hafnium Oxide Films for Ultraviolet Applications," Appl. Opt. 41, 3205-3210 (2002)