In this SBIR program, Structured Materials Industries, Inc. www.structuredmaterials.com (SMI) will develop tunable RF capacitors with ultra-low series resistance. The tunable capacitors will be based on the tunable dielectric material barium strontium titanate - BaxSr1-xTiO3 (commonly referred to as BST). Presently, two factors limit implementation of tunable BST capacitors in RF systems; 1) poor temperature stability and 2) high series resistance. SMI is presently leading a team to solve the temperature stability problem for BST capacitors. In this proposed SBIR program, we will solve the series resistance problem and remove the last remaining obstacle for commercial implementation of tunable BST capacitors in military and commercial products. In Phase I, SMI will implement a 4-part strategy to reduce series resistance for tunable BST capacitors; including optimization of the capacitor geometry, optimization of the metallization, optimization of the interface between the metal and the tunable dielectric, and optimization of the tunable dielectric composition profile. In Phase II, we will optimize the manufacturing processes and the tooling, and demonstrate a pathway to low-cost, high-volume production. We will also produce optimized BST capacitors in Phase II, and demonstrate performance and reliability far superior to any commercially available alternative.
Keywords: BST, ferroelectric, thin films, MOCVD, RF, tunable capacitors, low loss, low resistance
