A 1-V TFT-load SRAM using a two-step word-voltage method

A 1-V SRAM using a TFT load cell was developed. Key circuits for obtaining the low-voltage operation are a two-step word-voltage (TSW) method, a submicroampere boosted-level generator using a multivibrator, and a sense amplifier using low-threshold MOSFETs. An access time of 250 ns and a standby current of 0.23 mu A were achieved for a 4-kb test chip using a 10.2- mu m/sup 2/ TFT-load cell. This technology is applicable for high-density and single-battery operational SRAMS.>