Self‐Limited Switching Femtojoule‐Class RESET Energy Estimate in Deep‐Confine in‐Doped Sb 2 Te 3 Phase‐Change Memory

Programming energy, particularly RESET, limits phase‐change memory scaling by increasing heat dissipation, cross‐talk, and access‐device requirements. While substantial progress has been achieved by aggressively shrinking the electrode–PCM contact area and enhancing thermal confinement, further reductions become increasingly challenging. Here we demonstrate an orthogonal strategy: self‐limited switching in deep‐confined In‐doped Sb 2 Te 3 (InST) cells enabled by pulsed electrodeposition of a fully amorphous, composition‐uniform alloy. The devices deliver nanosecond RESET at microampere‐level currents with a mean RESET energy of ∼15 fJ ( n = 20), sustain 800 cycles under femtojoule‐level RESET pulses. Cross‐sectional TEM reveals partial crystallization within an amorphous matrix, consistent with a self‐limited conductive pathway that preserves a relatively high low‐resistance state and suppresses RESET current without further contact‐area reduction.