Conduction mechanisms responsible for leakage currents in RF sputtered HfO2 high-κ gate-oxide thin film MOS capacitors

Switching-behavior improvement in HfO2/ZnO bilayer memory devices by tailoring of interfacial and microstructural characteristics

“…(1), Due to the easily broken Zn-O bond caused by low dielectric constant of ZnO material, more V O s can be produce in the ZnO sublayer [14,20]. (2), The migration of O 2− in the ZnO layer is significantly stronger than that in the HfO 2 layer when the voltage is applied to the bilayer because most of applied field is across the former layer [46].…”

“…Recently, transition metal oxides and rare-earth oxides especially binary oxides, such as ZnO [11,12], TiO 2 [1,10], HfO 2 [13,14], TaO x [2,15], NiO [16], ZrO 2 [17], and CeO 2 [18], have attracted considerable attention for its potential application in RS memory because of their controllable compositions and easy charge migration. ZnO is an intriguing semiconducting material with many superior properties in electronics, such as wide direct bandgap of 3.37 eV, low dielectric constant of ∼9, high resistivity of 10 5 Ω•cm, high electron mobility, low temperature synthesis and thermal stability, which are widely used in many products [19,20].…”

“…HfO 2 seems to be a promising candidate material due to its high thermal stability, high dielectric constant (20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30), large bandgap (5.6-6 eV) and simple fabrication process [14]. Moreover, among the variety of technologies and materials proposed, HfO 2 -based RRAM devices have shown excellent performances such as excellent scalability (∼30 nm), good switching endurance (>10 12 cycles) and data retention (>10 years extrapolated) [32][33][34][35].…”