Effect of postdeposition annealing on the thermal stability and structural characteristics of sputtered HfO2 films on Si (100)
Effect of postdeposition annealing on the thermal stability and structural characteristics of sputtered HfO2 films on Si (100)
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DOI：
10.1016/j.susc.2004.11.042
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发表时间：
2005-02-10
期刊：
影响因子：
1.9
通讯作者：
Zhang, LD
中科院分区：
文献类型：
--
作者：
He, G;Liu, M;Zhang, LD
研究了直流反应磁控溅射生长的HfO2介电材料栅堆结构的热稳定性和结构特性。利用x射线衍射和x射线光电子能谱分析了HfO2薄膜的结构特征和化学状态与印后温度的关系。XRD谱图表明，生长的HfO2薄膜呈非晶态，退火后的HfO2薄膜随着退火温度的升高由四方相转变为单斜相，在高退火温度下形成多晶结构。Hf4f和O1s的XPS分析表明，生长的HfO2膜是非化学计量的。随着退火温度的升高，Hf4f和0 Is的峰不断向低结合能方向移动，表明HfO2正在形成化学计量膜。在低温下退火生长的薄膜，非化学量薄膜与部分SiOx在界面区形成反应，形成界面区硅酸盐，硅酸盐和SiOx中的Si-O- hf和Si-O键主要归属于XPS O1s峰。高温退火过程中，缺o的HfO2薄膜会从形成的硅酸盐界面层和氧环境中吸收氧原子，形成完全氧化的HfO2薄膜。(C) 2004 Elsevier B.V.版权所有
The thermal stability and structural characteristics for gate stack structure of HfO2 dielectrics grown by DC reactive magnetron sputtering were investigated. The structural characteristics and chemical states of the HfO2 films in relation to the postannealing temperature were examined by X-ray diffraction and X-ray photoelectron spectroscopy. XRD patterns demonstrate that the as-grown HfO2 films are amorphous and the structure of the annealed HfO2 films undergoes a transformation of tetragonal to monoclinic phase with increasing annealing temperature and forms a polycrystalline structure at high annealing temperature. Analysis of XPS of Hf4f and O1s gives evidence that the as-grown HfO2 film is nonstoichiometric. With increase of annealing temperature, both peaks of Hf4f and 0 Is keep on shifting towards lower binding energy, which indicates to be forming stoichiometric HfO2 film. Annealing the as-grown thin film at low temperature leads to the formation of silicate at the interfacial regime resulting from the reaction between the nonstoichiometric thin film and parts of SiOx formed at the interfacial regime, and the Si-O-Hf and Si-O bonds in the silicate and SiOx attributes greatly to the XPS O1s peaks. High temperature annealing process, the O-deficient HfO2 films Will absorb oxygen atoms from the formed silicate interfacial layer and the oxygen ambient to form the fully oxidized HfO2 thin films. (C) 2004 Elsevier B.V. All rights reserved.