Circuit implementations of the differential capacitance read scheme (DCRS) for ferroelectric random-access memories (FeRAM)

This paper presents two circuit implementations for the differential capacitance read scheme (DCRS) in ferroelectric random-access memories (FeRAM). Compared to the conventional read scheme, DCRS achieves a faster read access by activating the sense amplifiers immediately after a wordline is activated. By relying on the capacitance difference instead of the charge difference, DCRS avoids raising the highly capacitive platelines until after the read is complete. We have implemented this scheme in a 0.35-μm CMOS+Ferro test chip that includes an array of 256 × 32 2T-2C cells. The test chip measures an access time of 45 ns at a power supply of 3 V.