Tailoring Structure by the Zn-induced Tetrahedron to Enable High-Stability and Low-Transition-energy of Sb2Te Phase-Change Films

Sb2Te thin film exhibits remarkable crystallization speed, which allows rapid data conversion in phase change memory (PCM). Thermal stability is a key challenge to enable reliable data retention. Meanwhile, it is necessary to study the transition energy in the process of crystallization when the thermal stability of the amorphous state is improved. Herein, we demonstrated an alloying strategy to optimize thermal stability and transition energy. Zn was screened to be a promising alloying element. Nano-composite Zn0.75Sb2Te thin film was designed, which exhibited excellent thermal stability and optimized transition energy. The data retention temperature for 10 years (T10-yr) increased by - 218 %, and the transition energy consumption decreased by - 27 % compared with Sb2Te thin film. The enhancement of these properties originated from Zn-modified local chemical bonding. Zn induced the formation of tetrahedron with strong bonds (Zn-Te and Zn-Sb bonds) and dragged the atomic diffusion in amorphous phase to improve thermal stability. The structural disorder and complexity of the first and second nearest neighbors of atoms were stimulated by Zn alloying, which inhibited the carrier transports, increased the amorphous resistance, and reduced the transition energy in the process of crystallization.