On-chip optical sense strategy illustrated in the case of flash memory system

We proposed and demonstrated a novel scheme for simultaneous optical sense electric memory cell states aiming to enhance the data-reading speed showing significant improvement. For the traditional electrical read-out method, it is impossible to simultaneously sense the information from more than two memory cells on the same bit-line (BL). However, with photonics, different wavelengths do not interfere. Therefore, by converting each memory information into different optical wavelength signals, and multiplexing them (for all bit states) into a single optical waveguide, we can simultaneously sense all memory information and transmit them optically. Experimentally, we demonstrated SONOS (silicon-oxide-nitride-oxide-silicon) transistor as the memory cell, monolithically integrated with optical sense circuits (microring resonator, MRR). Results show that the effective reading speed can be enhanced by 1200 times with 100 nm spectrum ranges.