GeTe/CrSb₂Te superlattice-like thin film for excellent thermal stability and high phase change speed

Thermal stability and operation speed are two key challenges in phase change memory (PCM). This work reports GeTe/Cr_0.16Sb₂Te (GT/CrST) superlattice-like (SLL) films for both high operation speed and superior thermal stability. The thermal properties, phase change behaviors, microstructural evolution and the electrical performances are investigated in detail. Results show that [GT(8 nm)/CrST(2 nm)]₇ film possesses excellent ten-year data-retention (T_10-year=156 ºC), small density change rate (2.6%), ultrafast reversible phase change (0.5 ns), and low resistance drift coefficient (∼0.07). Furthermore, the [GT(8 nm)/CrST(2 nm)]₇ based PCM cell has the reversible operation time of as low as 8 ns and low power consumption of 8.1×10⁻¹² J. The two-dimensional finite element analysis confirms that the lower power consumption is ascribed to the existence of interfacial thermal resistance in SLL thin film, leading to the lower thermal conductivity. Results indicate that [GT(8 nm)/CrST(2 nm)]₇ thin film has great potential for PCM application with excellent thermal stability and phase change speed.