1. Field
The application relates to vapor deposition methods including, but not limited to, atomic layer deposition and chemical vapor deposition processes for forming lithium fluoride films.
2. Description of the Related Art
Lithium fluoride (“LiF”) is an interesting optical material with a large band gap—about 14 eV—and low refractive index—about 1.39 at 580 nm. These attributes make it a good window material in the ultraviolet region of electromagnetic radiation. LiF is sensitive to both high-energy electromagnetic radiation, such as X-rays and gamma rays, and low-energy electrons and ions, easily forming color centers. Because of this sensitivity, it can be utilized in imaging detectors and dosimetry. Additionally, LiF could be useful as a starting material for solid lithium ion conducting electrolyte materials when combined with transition metal fluorides.
LiF is commonly deposited by a number of different physical methods, including thermal evaporation and sputtering. In general, however, films deposited by these physical methods do not show good conformality.