SBIR-STTR Award

Silicon carbide is a leading new candidate for mirror blanks because of its high stiffness, relatively high thermal conductivity, and abrasion resistance. The base material contains pores or large grains, which make it difficult to provide a smooth front surface. Researchers have developed a process for using ECR chemical vapor deposition to deposit very smooth amorphous silicon carbide (SiC) on I 00 mm substrates. The material is easily polished to obtain a 10-20 A rms surface roughness. Researchers are scaling up this process to I coat large diameter optics. The main problems associated with scale-up involve plasma gas dynamics and fluid flows. Researchers are developing a general computational model to be used for designing the gas delivery system. An existing system to coat large-area optics with smooth, amorphous SiC is being modified.The potential commercial application as described by the awardee: Research will result in thin film coatings of silicon carbide for optics and many wear;resist,ant applications. The scale-up of this process is general and applicable for coatings of SiC, boron nitride, diamond-like carbon, silicon nitride, silicon dioxide, titanium nitride, etc.

This SBIR Phase II project will develop the High Density Physical Vapor Deposition (HDPVD) sputter source for the growth of useful oxide compounds such as superconducting Y1Ba2Cu307-x- (Yttrium-Barium-Copper-Oxide). Using an electron cyclotron resonance source to sustain an oxygen plasma, large current densities can be produced in the HDPVD source which will uniformly sputter a large diameter YBCO target when independently biased at low voltage. The large current density delivered to the sputtering target will yield high deposition rates without concomitant high energy negative ion bombardment of the deposited film, a problem typically associated with magnetron sputtering. This project will fully characterize the parameter space for the HDPVD source and develop a robust reproducible deposition process for the growth of high quality YBCO films over both the front and back-sides of 4-inch diameter LaA10 (Lanthanum Aluminum Oxide)substrates. The HDPVD source has already demonstrated high growth rates with uniform film thickness for metals deposited over 5-inch diameter substrates, and this process can produce high quality YBCO films with growth rates which are at least an order of magnitude larger than that obtainable with off-axis magnetron sputtering. Once a HTS process is developed, this project will aim to fully commercialize the HDPVD source and sell these sources to several potential customers in the HTS (high temperature superconductor) community. The HDPVD source could be used for the deposition of numerous oxide materials for a wide variety of commercial applications. For instance, one potential high volume application for YBCO films is switchable filter banks for installation in all U.S. cellular phone repeater stations. Furthermore, the HDPVD source could be utilized for other oxide materials such as ferroelectrics for high dielectric or RAM (random access memory) applications, thin film phosphors for use in emerging flat panel display technology, and a variety of non-linear optical materials for other emerging applications.