Atomic Layer Deposition of Sb<sub>2</sub>Te<sub>3</sub>/GeTe Superlattice Film and Its Melt‐Quenching‐Free Phase‐Transition Mechanism for Phase‐Change Memory
Chanyoung Yoo, Jeong Woo Jeon, Seungjae Yoon, Yan Cheng, Gyuseung Han, Wonho Choi, Byongwoo Park, Gwangsik Jeon, Sangmin Jeon, Woohyun Kim, Yonghui Zheng, Jong‐Ho Lee, Jun‐Ku Ahn, Sunglae Cho, Scott B. Clendenning, I. V. Karpov, Yoon Kyung Lee, Jung‐Hae Choi, Cheol Seong Hwang
Abstract
Abstract Atomic layer deposition (ALD) of Sb 2 Te 3 /GeTe superlattice (SL) film on planar and vertical sidewall areas containing TiN metal and SiO 2 insulator is demonstrated. The peculiar chemical affinity of the ALD precursor to the substrate surface and the 2D nature of the Sb 2 Te 3 enable the growth of an in situ crystallized SL film with a preferred orientation. The SL film shows a reduced reset current of ≈1/7 of the randomly oriented Ge 2 Sb 2 Te 5 alloy. The reset switching is induced by the transition from the SL to the (111)‐oriented face‐centered‐cubic (FCC) Ge 2 Sb 2 Te 5 alloy and subsequent melt‐quenching‐free amorphization. The in‐plane compressive stress, induced by the SL‐to‐FCC structural transition, enhances the electromigration of Ge along the [111] direction of FCC structure, which enables such a significant improvement. Set operation switches the amorphous to the (111)‐oriented FCC structure.