This Small Business Innovation Research (SBIR)Phase I project will develop a novel way to measure charge trapping in dielectrics. The feasibility of our method by applying it to the characterization of plasma enhanced chemical vapor deposition (PECVD) nitride and oxide will be demonstrated. The deposition chemistry of these materials leaves trap sites that capture charge when subjected to large electric fields. Trapped charge affects the stability and performance of micro-electro-mechanical (MEM) devices that employ these dielectrics. A novel technique that uses a resonant, electro-statically actuated mechanical structure to measure charge trapped in a suspended dielectric layer is proposed. The real part of the device impedance, measured using a network analyzer, can be correlated to changes in electric field in the dielectric resulting from trapped charge..
PECVD dielectrics are critical constituents in MEM devices that enable $3.5 Billion in annualized sales (optical components, RF components, and medical imaging components). Although the technique itself is not a commercial product, it is broadly applicable to the engineering of MEMs devices utilizing suspended PECVD dielectric layers, such as radio frequency (RF) switches and micro-mirrors. This control of charge trapping in highly process sensitive PECVD dielectrics will allow us to realize the full commercial potential of our ultrasound devices in medical imaging applications.
