Ultraviolet antireflection coatings for use in silicon detector design

Erika T Hamden; Frank Greer; Michael E Hoenk; Jordana Blacksberg; Matthew R Dickie; Shouleh Nikzad; D Christopher Martin; David Schiminovich

doi:10.1364/AO.50.004180

Ultraviolet antireflection coatings for use in silicon detector design

Appl Opt. 2011 Jul 20;50(21):4180-8. doi: 10.1364/AO.50.004180.

Authors

Erika T Hamden¹, Frank Greer, Michael E Hoenk, Jordana Blacksberg, Matthew R Dickie, Shouleh Nikzad, D Christopher Martin, David Schiminovich

Affiliation

¹ Department of Astronomy, Columbia University, 550 W. 120th Street, New York, New York 10025, USA. hamden@astro.columbia.edu

PMID: 21772406
DOI: 10.1364/AO.50.004180

Abstract

We report on the development of coatings for a charged-coupled device (CCD) detector optimized for use in a fixed dispersion UV spectrograph. Because of the rapidly changing index of refraction of Si, single layer broadband antireflection (AR) coatings are not suitable to increase quantum efficiency at all wavelengths of interest. Instead, we describe a creative solution that provides excellent performance over UV wavelengths. We describe progress in the development of a coated CCD detector with theoretical quantum efficiencies (QEs) of greater than 60% at wavelengths from 120 to 300 nm. This high efficiency may be reached by coating a backside-illuminated, thinned, delta-doped CCD with a series of thin film AR coatings. The materials tested include MgF(2) (optimized for highest performance from 120-150 nm), SiO(2) (150-180 nm), Al(2)O(3) (180-240 nm), MgO (200-250 nm), and HfO(2) (240-300 nm). A variety of deposition techniques were tested and a selection of coatings that minimized reflectance on a Si test wafer were applied to functional devices. We also discuss future uses and improvements, including graded and multilayer coatings.