Breaking the Speed-Stability Trade-off in Sb Films via Ge–Sb Bonding and Si Cluster Engineering for Ultrafast Optoelectronic Hybrid Memory

Abstract Optoelectronic hybrid phase change memory (OEH-PCM) is a promising candidate to overcome the "von Neumann bottleneck" in modern computing. However, the longstanding speed-stability trade-off—where ultrafast operation and high thermal stability are mutually exclusive—remains a critical barrier for practical applications. Here, we break this trade-off in Sb-based OEH-PCM via dual-dopant engineering with Ge and Si. The GeSi-codoped Sb (GSS) film achieves high thermal stability (ten-year data retention at 224 °C) alongside ultrafast operation (SET/RESET speeds of 104 ps/13 ps). At optimized Ge/Si concentrations (6.1 at.% Ge, and 8.8 at.% Si), a balanced performance is realized: SET speed of 26 ps, volume-change rate of 1.5%, resistance drift coefficient of 0.071 (150 °C), and ten-year data retention at 164 °C. Crucially, structural analyses reveal that Ge and Si play complementary roles: Ge forms Ge–Sb bonds to suppress grain growth via solid-solution strengthening, enhancing thermal stability, while Si confines pre-ordered Sb atomic clusters without forming Si–Sb bonds, preserving ultrafast crystallization kinetics. This synergy enables simultaneous breakthroughs in both operational speed and stability, positioning GSS films as an ideal material for next-generation ultrafast, high-stability memory applications.