Chip Demonstration of a High-Density (43Gb) and High-Search-Bandwidth (300Gb/s) 3D NAND Based In-Memory Search Accelerator for Ternary Content Addressable Memory (TCAM) and Proximity Search of Hamming Distance.

We demonstrated a high density (43Gb) in-memory search (IMS) fully-integrated chip with the ability of Live DEMO for search applications. It’s based on a 96-layer 3D NAND product, using our novel design of paired String-Select Line (SSL) inputs. It can accelerate exact TCAM and proximity Hamming-distance searches. The 128b SSL-inputs and 16KB BL’s (output match lines) achieve maximum search bandwidth up to 300Gb/sec, while the measured chip power is less than 400mW. For TCAM mode, large Vt window (>2V) exact search was demonstrated. The read disturb tests surpass 100M read without observable Vt shift. The post-1K cycled + baking tests pass the usual retention qualification requirements. For proximity search, the BL current of paired SSL-input is directly proportional to the normalized Hamming distance so that we can provide an efficient in-memory sorter for similarity search. Our 3D NAND IMS device is suitable for supporting general-purpose data retrieval applications and can significantly save system energy of data movements.