title: Flash Memory Featuring Low-Voltage Operation by Crystalline ZrTiO4Charge-Trapping Layer.
abstract: Crystalline ZrTiO4(ZTO) in orthorhombic phase with different plasma treatments was explored as the charge-trapping layer for low-voltage operation flash memory. For ZTO without any plasma treatment, even with a high k value of 45.2, it almost cannot store charges due the oxygen vacancies-induced shallow-level traps that make charges easy to tunnel back to Si substrate. With CF4plasma treatment, charge storage is still not improved even though incorporated F atoms could introduce additional traps since the F atoms disappear during the subsequent thermal annealing. On the contrary, nevertheless the k value degrades to 40.8, N2O plasma-treated ZTO shows promising performance in terms of 5-V hysteresis memory window by ±7-V sweeping voltage, 2.8-V flatband voltage shift by programming at +7 V for 100 μs, negligible memory window degradation with 105program/erase cycles and 81.8% charge retention after 104sec at 125 °C. These desirable characteristics are ascribed not only to passivation of oxygen vacancies-related shallow-level traps but to introduction of a large amount of deep-level bulk charge traps which have been proven by confirming thermally excited process as the charge loss mechanism and identifying traps located at energy level beneath ZTO conduction band by 0.84 eV~1.03 eV.
authors.affiliation: Department of Engineering and System Science, National Tsing Hua University, Hsinchu 30013, Taiwan.
authors.forename: Yung-Shao
authors.initials: YS
authors.lastname: Shen
authors.affiliation: Department of Engineering and System Science, National Tsing Hua University, Hsinchu 30013, Taiwan.
authors.forename: Kuen-Yi
authors.initials: KY
authors.lastname: Chen
authors.affiliation: Department of Engineering and System Science, National Tsing Hua University, Hsinchu 30013, Taiwan.
authors.forename: Po-Chun
authors.initials: PC
authors.lastname: Chen
authors.affiliation: Department of Engineering and System Science, National Tsing Hua University, Hsinchu 30013, Taiwan.
authors.forename: Teng-Chuan
authors.initials: TC
authors.lastname: Chen
authors.affiliation: Department of Engineering and System Science, National Tsing Hua University, Hsinchu 30013, Taiwan.
authors.forename: Yung-Hsien
authors.initials: YH
authors.lastname: Wu