Multi-layer heterojunction phase change thin films with extremely low resistance drift

Abstract

This work prepared [GeSb9 (x nm)/Ga3Sb7 (16-x nm)]5 multi-layer phase change thin films and studied their related properties. Compared to traditional GST and GeSb9, [GeSb9 (6 nm)/Ga3Sb7 (10 nm)]5 multi-layer phase change thin films have a higher crystallization temperature (∼205 °C) and an extremely low resistance drift coefficient (0.0004). The crystalline behavior and bonding of thin films are analyzed to elucidate their intrinsic mechanisms, thermal stability, and interfacial effects. According to crystal mechanism analysis, the Avrami index (n) is 0.904, indicating that the [GeSb9(6 nm)/Ga3Sb7(10 nm)]5 multi-layer phase change thin films grow in one dimension. The presence of interfaces alters the crystallization behavior of crystals, leading to a growth mode that transitions from diffusion-controlled to interface-controlled and back to diffusion-controlled. This transformation significantly reduces the nucleation index (m ≤ 0.16), minimizing the inherent randomness of the film itself and achieving extremely low resistance drift. Research has demonstrated that [GeSb9 (6 nm)/Ga3Sb7 (10 nm)]5 multi-layer phase change materials have promising applications in embedded memory.