Increasing the storage density of phase-change memory is a challenging subject towards the universal memory commercialization. Multi-level data storage can be implemented in phase-change memory cells by designing multiple stages of crystallization of phase-change materials, which is favorable to push forward the application of phase-change memory in storage-class memory and the emerging in-memory computing. Here, the structure and properties of In₂Se₃ phase-change thin films with multi-level phase transitions are investigated. The In₂Se₃ thin films changes resistance states twice upon heating with high crystallization temperature and good thermal stability. The amorphous In₂Se₃ thin films undergo partial crystallization of the Se phase followed by crystallization of the γ-In₂Se₃ phase, with successive stages of crystallization accounting for the three distinct levels of resistivity. The phase-change memory cell based on In₂Se₃ thin films shows a continuous switching process of high resistance state, intermediate resistance state and low resistance state with low drift coefficient in SET-RESET operations at a speed as fast as 60 ns, and the RESET power is as low as 311 pJ, indicating that the In₂Se₃ thin films have good performance of three-state storage property and can effectively improve the memory density.

提高相变存储器的存储密度是通用存储器商业化的一个具有挑战性的课题。通过设计相变材料的多级结晶，可以在相变存储单元中实现多级数据存储，有利于推动相变存储器在存储级存储器中的应用和新兴的内存中计算。_{在这里，研究了具有多级相变的 In 2} Se ₃相变薄膜的结构和性能。In ₂ Se ₃薄膜在加热时两次改变电阻态，晶化温度高，热稳定性好。非晶In ₂ Se ₃薄膜先经历 Se 相的部分结晶，然后是 γ-In ₂ Se ₃相的结晶，连续的结晶阶段导致三个不同的电阻率水平。_{基于In 2} Se ₃薄膜的相变存储单元在SET-RESET操作中表现出低漂移系数的高阻态、中阻态和低阻态的连续切换过程，速度快至60 ns，并且RESET功率低至311pJ，表明In ₂ Se ₃薄膜具有良好的三态存储性能，可有效提高存储密度。