X射线光电子能谱
原子层沉积
工作职能
退火(玻璃)
材料科学
金属浇口
电介质
化学键
氧化物
分析化学(期刊)
微晶
高-κ电介质
栅氧化层
光电子学
化学工程
纳米技术
薄膜
图层(电子)
化学
复合材料
晶体管
冶金
电气工程
工程类
色谱法
电压
有机化学
作者
Ekaterina Zoubenko,Sara Iacopetti,Kamira Weinfeld,Yaron Kauffmann,Patrick Van Cleemput,M. Eizenberg
出处
期刊:Journal of vacuum science & technology
[American Vacuum Society]
日期:2021-05-11
卷期号:39 (4)
被引量:6
摘要
This study investigates molybdenum deposited by atomic layer deposition (ALD) as a potential gate metallization for flash memory devices. Polycrystalline (110)-oriented, with low-resistivity (∼16 μΩ cm) ALD Mo films were deposited on SiO2 and Al2O3 using hydrogen reduction of Mo-oxychloride precursor. On SiO2, an effective work function (EWF) of 4.75 ± 0.1 eV was obtained for as-deposited samples, and its value increased up to 4.9 ± 0.05 eV upon annealing at 600 °C, whereas on Al2O3, a stable EWF value of 5.05 ± 0.05 eV was observed. The EWF variation is correlated with changes in the composition and chemical bonding at the metal/dielectric interface. The latter were investigated by energy dispersive x-ray spectroscopy and electron energy loss spectroscopy performed using scanning transmission electron microscopy and x-ray photoelectron spectroscopy. This analysis revealed that the presence of Mo oxide at the Al2O3/Mo interface stabilizes the EWF, and the EWF increase on SiO2 is attributed to Si enrichment at the SiO2/Mo interface upon annealing. A theoretical model is suggested to explain the chemical bonding difference on SiO2 and Al2O3, based on the Mo-precursor reactions with the surface groups of the dielectric. This study emphasizes the importance of the precursor/substrate reactions in determining the compositional and, therefore, electrical properties of the metal/dielectric interface, and demonstrates that ALD Mo deposited directly on SiO2 and Al2O3 is a promising candidate for gate metallization of flash devices due to its high EWF.
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