Structural and Thermodynamic Decoupling in 5 nm Transverse Orbitronic MRAM for Century-Scale Enterprise Non-Volatile Caches

Abstract Ultra-scaled spin-transfer torque (STT) and conventional spin-orbit torque (SOT) magnetoresistive random-access memory (MRAM) cells face an existential physics bottleneck at 5 nm node: the severe coupling of read and write paths within Two-Terminal layouts. Operating at sub-nanosecond precessional limits forces massive transient current spikes through thin oxide layers, driving catastrophic dielectric breakdown and severe thermal burnout. Here, we present a complete engineering framework for an ultra-scaled 5 nm decoupled Three-Terminal transverse orbitronic MRAM architecture that resolves these scaling trade-offs. By routing the write current horizontally through a monolayer polar 2D Cu2WSe4 (Wtrack = 6 nm, Ltrack = 12 nm), the vertical oxide barrier is structurally isolated from write stress, dropping the operational junction voltage drop to exactly Vops = 0.0 V. Combined with an integrated synthetic antiferromagnet (SAF) storage assembly and an adaptive +12% electrical current boost, this transverse design completely neutralizes adjacent magnetostatic and thermal cross-talk. Numerical modeling via stochastic Heun integration demonstrates a ballistic stable switching threshold at a target pulse width 74.5 ps, an operational temperature envelope extended up to 412.5 K (139.35°C), and a reduction in error correction code (ECC) requirements to ≲ 2 bits/block at the 85°C industrial limit. This multi-axial co-optimization expands the manufacturing tolerance window and establishes a concrete roadmap for a zero-degradation 100-year century enterprise non-volatile cache lifetime.