A Novel CMOS SRAM Feedback Element for SEU Environments

A hardened CMOS SRAM has been proposed which utilizes a leaky polysilicon Schottky diode placed in the feedback path to attain the SEU immunity of resistor-coupled SRAMs while improving the access speed of the cell. Novel polysilicon hybrid Schottky-resistor structures which emulate the leaky diodes have been designed and fabricated. The elements´ design criteria and methods of fulfilling them are presented along with a practical implementation scheme for CMOS SRAM cells.