Enhancing Stability at High Temperature in GaSb‐Based Phase‐Change Materials via Carbon Introduction

Phase‐change materials are key candidates for next‐generation nonvolatile memories, yet their reliability at elevated temperatures remains challenging. In this work, we investigate the effects of carbon introduction on GaSb‐based alloys to enhance thermal stability and data retention while minimizing mechanical stress. Systematic in situ X‐ray diffraction, sheet resistance, and X‐ray reflectivity analyses reveal that carbon incorporation significantly modifies the crystallization kinetics and structural evolution. At high C contents, the crystallization temperature increases by over 40°C (up to about 282°C), and the activation energy rises, indicating improved data retention. Simultaneously, carbon decreases Sb phase segregation, reduces grain sizes, and induces a compressive strain in the GaSb lattice, consistent with CSb bonds formation that limits atomic diffusion. Forwards‐backward sheet resistance measurements as a function of temperature confirm that the amorphous phase remains stable up to ∼270°C, nearly 90°C higher than in reference alloy without C. The resulting C‐incorporated GaSb exhibits a tenfold higher electrical contrast and an extrapolated 10 year stability of the as‐deposited amorphous phase at 187°C. With reduced density change upon crystallization (