Voltage and Energy-Delay Performance of Giant Spin Hall Effect Switching for Magnetic Memory and Logic

TL;DR

This paper demonstrates that Giant Spin Hall Effect (GSHE) MRAM can outperform traditional MTJ-based devices in energy, delay, and voltage at nanomagnet scales, by optimizing electrode geometry and spin injection efficiency.

Contribution

It introduces a detailed analysis of scaling effects on GSHE and MTJ devices, identifying optimal geometries for low voltage and high-speed operation, and derives energy-delay trajectories for improved MRAM performance.

Findings

GSHE MRAM achieves <0.1 V operation voltage.

Optimized GSHE devices reach 10 ps switching time.

Energy per bit as low as 100 aJ.

Abstract

In this letter, we show that Giant Spin Hall Effect (GSHE) MRAM can enable better energy- delay and voltage performance than traditional MTJ based spin torque devices at scaled nanomagnet dimensions (10-30 nm). Firstly, we derive the effect of dimensional scaling on spin injection efficiency, voltage-delay and energy-delay of spin torque switching using MTJs and GSHE and identify the optimum electrode geometry for low operating voltage (<0.1 V), high speed (>10 GHz) operation. We show that effective spin injection efficiency >100 % can be obtained using optimum spin hall electrode thickness for 30 nm nanomagnet widths. Finally, we derive the energy-delay trajectory of GSHE and MTJ devices to calculate the energy-delay product of GSHE and MTJ devices with an energy minimum at the characteristic time of the magnets. Optimized GSHE devices when combined with PMA can enable MRAM with scaled nanomagnets (30 nm X 60 nm), ultra-low voltage operation (< 0.1 V), fast switching times (10 ps) and switching energy as low as 100 aJ/bit.