期刊
JOURNAL OF ALLOYS AND COMPOUNDS
卷 722, 期 -, 页码 307-312出版社
ELSEVIER SCIENCE SA
DOI: 10.1016/j.jallcom.2017.06.036
关键词
Y-stabilized ZrO2; DRAM capacitor; Atomic layer deposition; High-k dielectric; Leakage current
资金
- National Research Foundation of Korea (NRF) - Korea government (MSIP) [NRF-2014R1A2A1A11052588]
- Global PH.D Fellowship Program through National Research Foundation of Korea (NRF) - Ministry of Education [2014021146]
- Air Liquide
With accelerated shrinking of integrated circuit, the fabrication of metal-insulator-metal (MIM) capacitors having a high capacitance density and low leakage current for dynamic random access memory (DRAM) has become a challenge. In this study, we investigated Y-stabilized ZrO2 as a novel high-k material for DRAM capacitors. We used atomic layer deposition (ALD) to produce Y-stabilized ZrO2; this technique enables easy control of the Y concentration by changing the ratio of ZrO2 to Y2O3 ALD cycles. This technique is suitable for future DRAM capacitors, as it provides superior thickness controllability and conformality. Y doping into ZrO2 increases the oxygen vacancy content in the films and transforms the ZrO2 crystal structure from monoclinic to cubic. As a result, the dielectric constant is significantly increased from 19.1 to 30.2. Moreover, Y doping shifts the defect level into the conduction band rather than the energy bandgap, resulting in about 60 times lower leakage current density for Y-doped ZrO2 compared to undoped ZrO2. It is notable that the dielectric properties and the leakage current density are simultaneously enhanced, indicating that Y-doped ZrO2 is a promising candidate to satisfy the requirements of future DRAM capacitors. (C) 2017 Elsevier B.V. All rights reserved.
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