STTR Phase I: Light Transparent, Electrically Conductive Coatings by Filtered Cathodic Arc Plasma Deposition

Alameda Applied Sciences Corporation, Oakland CA

Investigators

Abstract

This Small Business Technology Transfer (STTR) Phase I project proposes to develop a new class of UV-transmitting, electrically conductive coatings by using filtered cathodic arc plasma deposition (FCAPD). Cathodic arc plasmas are characterized by relatively high ion energy (20-150 eV) that lead to denser films. Macroparticles which typically contaminate such plasmas can be filtered using curved magnetic filters that have been developed by Berkeley's Plasma Application Group. Filtered cathodic arc coatings are not only dense but may be grown in a vacuum or reactive environments. The window of partial pressure for stochiometric compound films is wider than for evaporation or sputtering methods. Moreover, sputtered coatings (and more so beam-evaporated films) are characterized by porosity, which increases the thickness for the required electrical conductivity, with reduced optical transmission. The primary objective of Phase I is to demonstrate that a thin coating can be produced which is highly conductive and transmits between 80- 90% of the incident UV radiation. Once the feasibility of using FCAPD for producing high density coatings that show high electrical conductivity and high light transparency have been answered, Phase II will optimize the process for larger areas. Engineering development, marketing and sales of coating units is the province of Phase III. Commercial applications for FCAPD films include: electrochromic automotive and aircraft windows; heat mirrors; optoelectronic devices such as UV triggered diamond high voltage switches; solar cell surfaces for space applications Cathodic arc deposition of TiN coatings is a well established technology which supports tens of millions of dollars of business annually worldwide in coating equipment sales and hundreds of millions of dollars annually for the coatings generated by that equipment.