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

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.