Enhancement of multilayer coated normal incidence gratings in the extreme ultraviolet using a CNx smoothing layer

Robert A. Stern*, Lawrence Shing, Yip-Wah Chung, Murat Guruz

*Corresponding author for this work

Research output: Contribution to journalConference articlepeer-review

1 Scopus citations

Abstract

We describe a novel process to improve the extreme ultraviolet (EUV) reflection efficiency of multilayer-coated replica gratings through an intermediate CNX overcoat. Au-coated and uncoated (SiO2 surface) Hitachi replica gratings (20 × 20 mm, 4800 g/mm, 13° blaze angle), designed to provide peak efficiencies at 304 Å in 3rd order, were measured using an AFM prior to and after the CNX coating. The CNX coating produced substantially smoother grating facets without significantly degrading the grating groove profile. The gratings were then overcoated with a 10 layer Mo/Si stack optimized for near normal reflectivity at 304 Å. Reflectivity measurements in 3rd order demonstrated an enhancement in absolute grating efficiency by a factor of 4 over the Mo/Si + Au-coated grating. The results of this simple experiment suggest that, with further improvements, the CNX overcoating process may provide a useful and relatively inexpensive alternative to the use of ion-etched blazed gratings in the EUV for some applications.

Original languageEnglish (US)
Pages (from-to)61-71
Number of pages11
JournalProceedings of SPIE - The International Society for Optical Engineering
Volume4854
DOIs
StatePublished - Dec 1 2002
EventFuture EUV/UV and Visible Space Astrophysics Missions and Instrumentation - Waikoloa, HI, United States
Duration: Aug 22 2002Aug 23 2002

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Condensed Matter Physics

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