Tristan Bret

In situ control of the focused-electron-beam-induced deposition process

A simple quantitative method for in situ control of the focused-electron-beam-induced deposition process is discussed and demonstrated with precursors used for Au, Cu, Rh, and SiO2 deposition. A picoamperemeter monitors the electron current flowing through the sample, which reproducibly drops at a characteristic rate to a plateau value during deposition. These parameters are correlated to deposit geometry, composition, and precursor supply. Monte Carlo simulations of electron backscattering and secondary electron emission by the growing structures show excellent agreement with the experiment. The method could apply to a wide range of charged-particle deposition and etching processes.

Comparison of fabrication methods of sub-100nm nano-optical structures and devices

Nano-optical devices are raising more and more interest for a variety of applications. From single molecule detection at high molecular concentration by Fluorescence Correlation Spectroscopy (FCS) through optical multiplexing with photonic crystal structures into the exciting field of negative index of refraction materials, the hardware functional dimensions and surely the tolerances are reaching the lower tens of nanometer range. The fabrication of such devices, i.e. the machining of optically interesting materials and material combinations (dielectric, semiconducting, or metallic) at this scale needs adaptation of classical nanostructuring technologies like Electron Beam Lithography (EBL), or the application of serial direct machining technologies like Focused Charged Particle Beam Etching or Deposition with electrons or Ga ions. For low excitation volume FCS measurements, EBL is used for production of high quality nanoscale sub-wavelength apertures in optically opaque (150 nm thick) metal films. The process consists in high aspect ratio patterning of a thick negative e-beam resist film followed by metal lift off. The optically transparent substrate allows the production of any 2D aperture geometry. Difficulties of the production process and their limits are presented. Direct serial machining with charged particle beams shows excellent flexibility and is an interesting 3D alternative method. Deposition by decomposing volatile chemicals under an ion/electron probe, which can be as small as 7nm/1nm, this technique allows for rapid, local prototyping of 2D and 3D nano-structures with highest lateral and axial resolution. The deposited material can be tuned to homogeneous, nanocomposite or crystalline, metallic or transparent, opening the way to applications in photonic crystals and plasmonics. An original in-situ micro-reflectometry method permits the real time control of the growth of the deposits.

A mechanistic study of GaN laser lift-off

Keywords: [NRG] Reference LOA-ARTICLE-2002-009doi:10.1002/1521-396X(200212)194:2 3.0.CO;2-S URL: \\ATLANTIS\Mad\MAD public\Publi Present Conferences\Publications\printed papers\2002\NRG-Bret-PSS-2002-352.pdf Record created on 2009-07-20, modified on 2017-05-10