A low voltage operation 1 Mbit SRAM with a polysilicon resistor load memory cell has been developed. This SRAM adopts a new boost circuit which operates continuously for both write and read operation at the optimized boost-level. An access time of 225 ns at V-cc = 1.6 V is achieved. This paper also describes the minimum operating voltage (V-ccmin) dependence on the threshold voltage and cell ratio of the symmetrical memory cell.