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Title: Ultraviolet optical properties of aluminum fluoride thin films deposited by atomic layer deposition

Aluminum fluoride (AlF{sub 3}) is a low refractive index material with promising optical applications for ultraviolet (UV) wavelengths. An atomic layer deposition process using trimethylaluminum and anhydrous hydrogen fluoride has been developed for the deposition of AlF{sub 3} at substrate temperatures between 100 and 200 °C. This low temperature process has resulted in thin films with UV-optical properties that have been characterized by ellipsometric and reflection/transmission measurements at wavelengths down to 200 nm. The optical loss for 93 nm thick films deposited at 100 °C was measured to be less than 0.2% from visible wavelengths down to 200 nm, and additional microstructural characterization demonstrates that the films are amorphous with moderate tensile stress of 42–105 MPa as deposited on silicon substrates. X-ray photoelectron spectroscopy analysis shows no signature of residual aluminum oxide components making these films good candidates for a variety of applications at even shorter UV wavelengths.
Authors:
; ; ;  [1]
  1. Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109 (United States)
Publication Date:
OSTI Identifier:
22489753
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films; Journal Volume: 34; Journal Issue: 1; Other Information: (c) 2015 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ALUMINIUM FLUORIDES; DEPOSITION; DEPOSITS; HYDROGEN FLUORIDES; LOSSES; MICROSTRUCTURE; PRESSURE RANGE MEGA PA 100-1000; REFRACTIVE INDEX; SUBSTRATES; TEMPERATURE RANGE 0400-1000 K; THIN FILMS; ULTRAVIOLET RADIATION; WAVELENGTHS; X-RAY PHOTOELECTRON SPECTROSCOPY