IG-CRM: Area/Energy-Efficient IGZO-Based Circuits and Architecture Design for Reconfigurable CIM/CAM Applications

Artificial intelligence is evolving with various algorithms such as deep neural network (DNN), Transformer, recommendation system (RecSys) and graph convolutional network (GCN). Correspondingly, multiply-accumulate (MAC) and content search are two main operations, which can be efficiently executed on the emerging computing-in-memory (CIM) and content-addressable-memory (CAM) paradigms. Recently, the emerging Indium-Gallium-Zine-Oxide (IGZO) transistor becomes a promising candidate for both CIM/CAM circuits, featuring ultra-low leakage with >300s data retention time and high-density BEOL fabrication. This paper proposes IG-CRM, the first IGZO-based circuits and architecture design for Reconfigurable CIM/CAM applications. The main contributions include: 1) at cell level, propose IGZO-based 3T0C/4T0C cell design that enables both CIM and CAM functionalities while matching IGZO/CMOS voltage; 2) at circuit level, utilize the BEOL IGZO transistor to reduce digital adder tree area in CIM circuits; 3) at architecture level, propose a reconfigurable CIM/CAM architecture with four macro structures based on 3T0C/4T0C cells. The proposed IG-CRM architecture shows high area/energy efficiency on various applications including DNN, Transformer, RecSys and GCN. Experiment results show that IG-CRM achieves 8.09X area saving compared with the SRAM-based non-reconfigurable CIM/CAM baseline, and 1.53×103X/51.9X speedup and 1.63×104X/7.62×103X energy efficiency improvement compared with CPU and GPU on average.