Lirong Sun

Tunable stoichiometry of BCxNy thin films through multitarget pulsed laser deposition monitored via in situ ellipsometry

Abstract. Pulsed laser deposition is an energetic deposition technique in which thin films are deposited when a laser pulse at 248-nm wavelength strikes a target and material is subsequently deposited onto a substrate with ideally the same stoichiometry. By synchronizing a high-speed mirror system with the pulsing of the laser, and using two separate targets, thin films having tunable stoichiometry have been deposited. Depositions were performed in a high vacuum environment to obtain as much kinetic energy as possible during growth. Typically, some 150 pulses at 300  mJ/pulse were required to deposit 1 nm. Island growth must occur on a per pulse basis since over 100 pulses are required to deposit a 1 nm film thickness. Films were deposited to ∼100-nm thickness, and in situ ellipsometry data were modeled to calculate thickness, n and k. X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and atomic force microscopy (AFM) were all performed on each of the films. XPS demonstrated change in film composition with change in laser pulse ratio; ellipsometry displayed thickness from the model generated as well as the optical properties from 370 to 1690 nm. AFM thickness measurements were in agreement with independently modeled ellipsometry thickness values.

Tunable Stoichiometry of SiOx-BaTiOy-BOz Fabricated by Multitarget Pulsed Laser Deposition

Abstract. Oxide materials of desired stoichiometry are challenging to make in small quantities. Nanostructured thin films of multiple oxide materials were obtained by using pulsed laser deposition and multiple independent targets consisting of Si, BaTiO3, and B. Programmable stoichiometry of nanostructured thin films was achieved by synchronizing a 248-nm krypton fluoride excimer laser at an energy of 300  mJ/pulse, a galvanometer mirror system, and the three independent target materials with a background pressure of oxygen. Island growth occurred on a per pulse basis; some 500 pulses are required to deposit 1 nm of material. The number of pulses on each target was programmed with a high degree of precision. Trends in material properties were systematically identified by varying the stoichiometry of multiple nanostructured thin films and comparing the resulting properties measured using in situ spectroscopic ellipsometry, capacitance measurements including relative permittivity and loss, and energy dispersive spectroscopy (EDS). Films were deposited ∼150 to 907 nm thickness, and in situ ellipsometry data were modeled to calculate thickness n and k. A representative atomic force microscopy measurement was also collected. EDS, ellipsometry, and capacitance measurements were all performed on each of the samples, with one sample having a calculated permittivity greater than 20,000 at 1 kHz.

Optical Multichannel Imaging of Pulsed Laser Deposition of ZnO

Pulsed laser deposition is an efficient technique to obtain stoichiometric material transfer from target to substrate and has been used by researchers and in industry for depositing materials for use in applications ranging from hard coatings and superconductors to optical materials. The images detailed here will demonstrate the unique plume evolution that occurs and the high-speed ionic species, and slow-speed neutral and molecular species that travel from target material to substrate.

Modeling and simulation of reactive magnetron co-sputtering for mixed oxide coatings

This work details the development and validation of a variant of the “Berg model for reactive sputtering” that is capable of predicting the chemical valence state of reactively co-sputtered Mo-Ge-O thin films.

Publisher’s note: Tunable stoichiometry of BCxNy thin films through multitarget pulsed laser deposition monitored via in situ ellipsometry

This article [J. Nanophoton.. 8, (1 ), 083890 ( Feb 5 , 2014)] mistakenly appeared in the Special Section on Metamaterials and Photonic Nanostructures. It was republished in the Special Section on Nanostructured Thin Films VI with a corrected CID on 10 February 2014. The updated citation is shown below: