Study of Ion Implanted Copper Laser Mirrors by Spectroscopic Ellipsometry
- PDF / 223,064 Bytes
- 6 Pages / 420.48 x 639 pts Page_size
- 94 Downloads / 190 Views
STUDY OF ION IMPLANTED COPPER LASER MIRRORS BY SPECTROSCOPIC ELLIPSOMETRY+ P.G. SNYDER*, A. MASSENGALE*, K. MEMARZADEH*, J.A. WOOLLAM*, and P.P. PRONKO** *University of Nebraska, Lincoln, NE 68588-0511 **Universal Energy Systems, Dayton, OH 45432
D.C.
INGRAM**
ABSTRACT Implantation with 400 keV Ag or Cu ions improves the near-surface microstructural
quality and reflectance of diamond turned and mechanically
polished flat copper laser mirrors.
Spectroscopic ellipsometry is sensitive
to changes in either the microscopic surface roughness, or in the nearsurface substrate void fraction, and both parameters are observed to change upon implantation. about 5 x 10 5cm- 2 .
Substrate density as a function of ion fluence peaks at Low energy (300 eV) Ar ion implantation can cause
either a reduction or increase in microscopic surface roughness, depending on fluence. INTRODUCTION The effects of ion implantation on diamond turned (DT)
and mechanically
polished copper laser mirror surfaces are determined by variable angle of incidence spectroscopic ellipsometric (VASE) analysis. VASE is used to determine the relative microstructure of each surface [1-3]. We compare the starting surface microstructural quality of DT and polished mirrors, and the effect of implantation with Ag or Cu ions at different energies and over a range of fluences. SAMPLES AND EXPERIMENT Copper laser mirror substrates,
38 mm in diameter,
were mechanically
polished or diamond turned, with specified surface finishes of 10 nm r.m.s. or better, and flatness better than 100 nm. Up to 6 regions on each mirror were implanted, ions.
at room temperature, with different fluences of Ag, Cu or Ar
Mirror preparation and implantation information are summarized in
Table 1. The 400 keV implants of Ag and Cu were performed at U.E.S. with a 1.7 MVTandetron accelerator at normal incidence, with a beam current of about IpA/cm2 . The 300 eV Ar bombardments were performed at U.E.S. with a 2.5 cm Kaufman ion source incident at 450 to the sample using a current density of about imA/cm2. The spectroscopic ellipsometer has been described elsewhere [2].
Data
were obtained for each mirror at two angles of incidence (f), 700 and 73.50, for photon energies from 1.55 to 4.13 eV. Mat. Res. Soc. Symp. Pro
Data Loading...
