A NOVEL METAL-INSULATOR METAL STRUCTURE FOR FIELD-PROGRAMMABLE DEVICES

A novel metal-insulator-metal (MIM) capacitor structure has been developed for use in field-programmable gate arrays (FPGA's) as a voltage-programmable link (VPL). The new structure relies on a combination of a refractory metal and aluminum as the lower electrode, and either a similar combination or aluminum alone as the top electrode. The insulator is prepared by means of plasma-enhanced chemical vapor deposition (PECVD); it comprises a sandwich of nearly stoichiometric silicon dioxide interposed between two like layers of silicon-rich silicon nitride. The present structure has displayed characteristics desirable for use in the emerging FPGA technology including high density, low on-resistance, reduced capacitance, and low programming voltage.