Special kinetics features of scandium antimonide thin films conducive to swiftly embedded phase-change memory applications

具有独特动力学性质的锑化钪薄膜用于快速嵌入式相变存储

Embedded phase-change random-access memory(ePCRAM)applications demand superior data retention in amorphous phase-change materials(PCMs).Traditional PCM design strategies have focused on enhancing the thermal stability of the amorphous phase,often at the expense of the crystallization speed.While this approach supports reliable microchip operations,it compromises the ability to achieve rapid responses.To address this limitation,we modified ultrafast-crystallizing Sb thin films by incorporating Sc dopants,achieving the highest 10-year retention temperature(~175℃)among binary antimonide PCMs while maintaining a sub-10-ns SET operation speed.This reconciliation of two seemingly contradictory properties arises from the unique kinetic features of the 5-nm-thick Sc12Sb88 films,which exhibit an enlarged fragile-to-strong crossover in viscosity at medium supercooled temperature zones and an incompatible sublattice ordering behavior between the Sc and Sb atoms.By tailoring the crystallization kinetics of PCMs through strategic doping and nanoscale confinement,we provide new opportunities for developing robust yet swift ePCRAMs.

嵌入式相变存储器要求硫系相变存储材料具有良好的非晶相数据保持力.传统增强非晶相稳定性的方法往往不得不牺牲掉结晶速率;此举虽有助于提升终端器件运行的可靠性,但会导致器件响应较慢.为解决此问题,本文在具有快速结晶速率的Sb薄膜中掺入Sc,所设计的锑化钪Sc_(12)Sb_(88)材料不仅十年数据保持力达到~175℃,为目前报道Sb基二元相变材料的最高水平,而且其器件的响应速度可快至10 ns.之所以能兼具这两种相互矛盾的性能是因为5nm厚Sc_(12)Sb_(88)薄膜材料具有独特的动力学性质:在其中度过冷温区内,材料粘度发生了增强的脆性-强性转变,而且结构有序化过程中Sc和Sb会形成两种互不兼容的亚晶格结构.此发现表明,通过有策略的选择掺杂元素和采用纳米尺度限定的手段可以有效调控相变材料的结晶动力学,是实现兼具快速和稳定的嵌入式相变存储器的可行之道.