Title :
Reduced Threshold Current in NbO2 Selector by Engineering Device Structure
Author :
Xinjun Liu ; Nandi, Sanjoy Kumar ; Venkatachalam, Dinesh Kumar ; Belay, Kidane ; Song, Seunghyun ; Elliman, Robert Glen
Author_Institution :
Dept. of Electron. Mater. Eng., Australian Nat. Univ., Canberra, ACT, Australia
Abstract :
The leakage current scaling issues for NbO2 selector devices are investigated. By introducing a rough Pt bottom electrode (BE) (RMS roughness ~2.5 nm) and inserting a 20-nm-thick dielectric layer (Nb2O5 and HfO2) between the BE and NbO2 layer, we show that the threshold current for the insulator-metal-transition in microscale devices (~150 μm) can be reduced to ~20 μA, close to that realized in nanoscale (~10 nm) 3-D vertical ReRAM. This could be attributed to a thermal confinement effect caused by the presence of a permanent conductive filament in dielectric layer. The experimental results are supported by finite element simulation.
Keywords :
conducting materials; dielectric devices; dielectric materials; electrochemical electrodes; finite element analysis; hafnium compounds; leakage currents; niobium compounds; platinum; random-access storage; 3D vertical ReRAM; BE; Pt-Nb2O5-HfO2-NbO2; dielectric layer; engineering device structure; finite element simulation; insulator-metal-transition; microscale device; permanent conductive filament; reduced threshold leakage current scaling issue; rough bottom electrode; selector device; size 20 nm; thermal confinement effect; Dielectrics; Electrodes; Hafnium compounds; Materials; Nanoscale devices; Switches; Threshold current; Non-volatile memory; cross-point memory; cross-point memory.; niobium oxide; resistive switching; threshold switching;
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2014.2344105
