Phase Change Logic via Thermal Cross-Talk for Computation in Memory

TL;DR

This paper demonstrates a novel approach to logic computation using phase change memory devices that leverage thermal cross-talk, enabling smaller CMOS footprints and fast, non-volatile switching.

Contribution

It introduces a new method of using thermal cross-talk in phase change devices for logic operations, reducing CMOS footprint by approximately 50% and integrating with CMOS circuitry.

Findings

Thermal cross-talk enables toggle operations in phase change memory.

The approach reduces CMOS footprint by about 50%.

Switching speeds are in the nanosecond range and are non-volatile.

Abstract

We have computationally demonstrated logic function implementations using lateral and vertical multi-contact phase change devices integrated with CMOS circuitry, which use thermal cross-talk as a coupling mechanism to implement logic functions at smaller CMOS footprints. Thermal-crosstalk during the write operations is utilized to recrystallize the previously amorphized regions to achieve toggle operations. Amorphized regions formed between different pairs of write contacts are utilized to isolate read contacts. Typical expected reduction in CMOS footprint is ~ 50% using the described approach for toggle-multiplexing, JK-multiplexing and 2x2 routing. The switching speeds of the phase change devices are in the order of nanoseconds and are inherently non-volatile. An electro-thermal modeling framework with dynamic materials models are used to capture the device dynamics, and current and voltage requirements.