A HfO 2 /site based dual-layer selector device with minor threshold voltage variation

Abstract

Volatile programmable metallization cell is a promising threshold switching selector with excellent characteristics and simple structures. However, the large variation of threshold voltage is a major problem for practical application. In this work, we propose a dual-layer structure to increase selectivity and improve the threshold voltage variation. Compared to single-layer devices, this dual-layer device exhibits higher selectivity (>10 7 ) and better threshold voltage uniformity with less than 5% fluctuation during 200 DC switching. The improvement is attributed to good control on the location of the filament formation and rupture after introducing a HfO 2 layer. It is deduced that a major factor consists of the difference of Ag ions mobility between SiTe and HfO 2 due to the grain boundary quantity.