In-Memory Compute Chips with Carbon-based Projected Phase-Change Memory Devices

Achieving sufficient compute precision in matrix-vector multiply (MVM) operations is a key challenge for analog in-memory computing (AIMC) that relies on resistive memory devices. A device-level concept that addresses this challenge is that of projected-type phase-change memory (Proj-PCM). Here we present Proj-PCM devices based on carbon-based projection layer (CPL). We integrated these devices onto multi-tile AIMC chips fabricated in 14nm CMOS technology. CPL is shown to exhibit superior compatibility with the phase-change material layer (PCML) as well as the BEOL process. CPL also provides sufficient tunability of resistance window. The compute tiles with CPL-based Proj-PCM are shown to achieve higher computational precision compared to those with standard PCM devices.