Single-Ferroelectric Memcapacitor-Based Time-Domain Content-Addressable Memory for Highly Precise Distance Function Computation

Single ferroelectric memcapacitor-based time-domain (TD) content-addressable memory (CAM) is proposed and experimentally demonstrated for high reliability and density. The proposed TD CAM features the symmetric capacitance-voltage characteristics of a ferroelectric memcapacitor with a gated p-i-n diode structure. This CAM performs search operations based on the variable capacitance of cells. The propagation delay of the TD CAM output signal is linearly correlated with the Hamming distance (HD) between input and output vectors. The proposed TD CAM array exhibits exceptional reliability in HD computation and in-memory search tasks owing to this linearity, considerably outperforming the conventional nonlinear voltage-domain CAM.