1. Taiyuan University of Technology, Taiyuan, Shanxi 030024, China
2. National Institute of Metrology, Beijing 100029, China
3. Industrial Technology Research Institute, Hsinchu 30011, China
4. Korea Research Institute of Standards and Science,Daedeok 305-340, Korea
5. National Metrology Institute of Japan,Tsukuba 305-8565, Japan
Abstract In order to establish a reliable thickness-measuring fitting model for approximate 1 nm thickness HfO2 film using spectroscopic ellipsometry, the thickness of a ultrathin HfO2 film was measured by a grazing incidence X-ray reflection diffractometer, which belongs to a part of country / region interlaboratory comparison and it used as the reference value of ellipsometry model thickness. It investigated the selected dispersion model and fitting parameters of HfO2 film. The results show that the optimized fitting conditions are obtained, and Tauc-Lorentz 3 for the dispersion model is selected with wavelength ranging from 3.45 eV to 4.35 eV and the ratio of the HfO2 to porosity equals 60:40.
［1］Fukuda H, Yasuda M, Iwabuchi T. Characterization of SiO2/Si (100) interface structure of ultrathin SiO2 films using spatially resolved electron energy loss spectroscopy［J］. Applied physics letters, 1992, 61(6): 693-695.
［2］Hubbard K J, Schlom D G. Thermodynamic stability of binary oxides in contact with silicon［J］. Journal of Materials Research, 1996, 11(11): 2757-2776.
［3］Billman C A, Tan P H, Hubbard K J, et al. Alternate gate oxides for silicon MOSFETs using high-K dielectrics［J］. MRS Online Proceedings Library, 1999, 567:409-414.
［4］Schlom D G, Billman C A, Haeni J H, et al. High-K candidates for use as the gate dielectric in silicon mosfets［M］//Thin films and heterostructures for oxide electronics. Springer US, 2005: 31-78.
［5］Schlom D G, Haeni J H. A thermodynamic approach to selecting alternative gate dielectrics［J］. MRS bulletin, 2002, 27: 198-204.
［6］Lim S G, Kriventsov S, Jackson T N, et al. Dielectric functions and optical bandgaps of high-K dielectrics for metal-oxide-semiconductor field-effect transistors by far ultraviolet spectroscopic ellipsometry［J］. Journal of applied physics, 2002, 91(7): 4500-4505.
［7］张继涛, 李岩, 罗志勇. 一种可溯源的光谱椭偏仪标定方法［J］. 物理学报, 2010, 59(1): 186-191.
［8］Stoev K N, Sakurai K. Review on grazing incidence X-ray spectrometry and reflectometry［J］. Spectrochimica Acta Part B: Atomic Spectroscopy, 1999, 54(1): 41-82.
［9］Chen T C, Peng C Y, Tseng C H, et al. Characterization of the Ultrathin HfO 2 and Hf-Silicate Films Grown by Atomic Layer Deposition［J］. IEEE Transactions on Electron Devices, 2007, 54(4): 759-766.
［10］刘文德, 陈赤, 陈熙, 等. 光刻胶光学性质的光谱椭偏测量方法研究［J］. 计量学报, 2011, 32(4): 381-384.
［11］Sancho-Parramon J, Modreanu M, Bosch S, et al. Optical characterization of HfO2 by spectroscopic ellipsometry: dispersion models and direct data inversion［J］. Thin Solid Films, 2008, 516(22): 7990-7995.
［12］Dane A D, Veldhuis A, de Boer D K G, et al. Application of genetic algorithms for characterization of thin layered materials by glancing incidence X-ray reflectometry［J］. Physica B: Condensed Matter, 1998, 253(3): 254-268.
［13］Logothetidis S, Stergioudis G. Studies of density and surface roughness of ultrathin amorphous carbon films with regards to thickness with X-ray reflectometry and spectroscopic ellipsometry［J］. Applied physics letters, 1997, 71(17): 2463-2465.
［14］Liang Y, Curless J, Tracy C J, et al. Interface dipole and effective work function of Re in Re/HfO2/SiOx/n-Si gate stack［J］. Applied physics letters, 2006, 88(7): 2907.
［15］Ren L L, Gao H F, Gao S T, et al. Determination of multilayer thicknesses of GaAs/AlAs superlattice by grazing incidence X-ray reflectivity［J］. International Journal of Metrology and Quality Engineering, 2013, 4(2): 81-86.
［16］Jia Y, Gao H, Li X, et al. The thickness measurement of ultrathin films from new high-k material HfO2 by grazing incidence X-ray reflectivity［J］. Materials Research Express, 2016, 3(6): 065015.
［17］Balog M, Schieber M, Michman M, et al. Chemical vapor deposition and characterization of HfO2 films from organo-hafnium compounds［J］. Thin Solid Films, 1977, 41(3): 247-259.
［18］Lehan J P, Mao Y, Bovard B G, et al. Optical and microstructural properties of hafnium dioxide thin films［J］. Thin Solid Films, 1991, 203(2): 227-250.
［19］Jellison Jr G E, Modine F A. Parameterization of the optical functions of amorphous materials in the interband region［J］. Applied Physics Letters, 1996, 69(3): 371-373.
［20］Wooten F. Optical properties of solids［M］. New York:Academic press, 2013.
［21］Tauc J, Grigorovici R, Vancu A. Optical properties and electronic structure of amorphous germanium［J］. physica status solidi (b), 1966, 15(2): 627-637.
［22］Ferrieu F, Dabertrand K, Lhostis S, et al. Observation of HfO2 thin films by deep UV spectroscopic ellipsometry［J］. Journal of Non-Crystalline Solids, 2007, 353(5): 658-662.
［23］Bruggeman D A G. Calculation of various physical constants of heterogeneous substances. II. Dielectric constants and conductivities of polycrystals in the non-regular systems (Sb Bi Sn Cd Hg)［J］. Annalen Der Physik, 1936, 25: 645-671.
2017, Vol. 38 
