High Speed and Bending Resistance Flexible Phase Change Memory Devices Based on Carbon-Doped Sb₂Te

In this study, we introduce carbon-doped Sb2Te (CST21) films and flexible phase change memory (FPCM) devices fabricated on polyimide (PI) substrates. The CST21 films exhibit remarkable mechanical and thermal stability, maintaining their phase transition capability even after 100 h of bending at various radii. Thermal cycling tests between 40 and 100 °C for 24 cycles further confirm the films’ excellent thermal stability. Structural and vibrational analyses reveal that the crystal structure and bonding characteristics of the films remain largely unaffected after prolonged bending at radii of 20 and 5 mm. While the films retain a smooth surface at a 20 mm bending radius, a 5 mm radius induces stress concentration, leading to surface cracks and increased roughness. FPCM crossbar devices based on CST21 were fabricated using a photolithographic process, with devices featuring a 2 μm line width demonstrating superior electrical performance compared to their 5 μm counterparts. These devices achieve a high switching speed of ∼6 ns, excellent cycling endurance (∼3000 cycles), a retention time exceeding 103 s and a low resistance drift (0.004). Notably, even after 4000 bending cycles at a 5 mm radius, the devices maintain a clear distinction between high and low resistance states. This work provides a promising strategy for developing FPCM devices with high operation speed and excellent bending resistance, offering potential for next-generation flexible electronics.