Wang Zhongjian

An analytical model for coplanar waveguide on silicon-on-insulator substrate with conformal mapping technique

In this paper, the authors present an analytical model for coplanar waveguide on silicon-on-insulator substrate. The four-element topological network and the conformal mapping technique are used to analyse the capacitance and the conductance of the sandwich substrate. The validity of the model is verified by the full-wave method and the experimental data. It is found that the inductance, the resistance, the capacitance and the conductance from the analytical model show they are in good agreement with the corresponding values extracted from experimental S-parameter until 10 GHz.

采用水基原子层沉积工艺在石墨烯上沉积Al 2 O 3 介质薄膜研究

采用水基原子层沉积(H 2 O-based ALD)方法在石墨烯上直接生长Al 2 O 3 介质薄膜, 研究了Al 2 O 3 成核机理. 原子力显微镜(AFM)对Al 2 O 3 薄膜微观形态分析表明, 沉积温度决定着Al 2 O 3 在石墨烯表面的成核生长情况, 物理吸附在石墨烯表面的水分子是Al 2 O 3 成核的关键, 物理吸附水分子的均匀性直接影响Al 2 O 3 薄膜的均匀性. 在适当的温度窗口(100~130℃), Al 2 O 3 可以均匀沉积在石墨烯上, AFM测得Al 2 O 3 薄膜表面均方根粗糙度(RMS)为0.26 nm, X射线光电子能谱(XPS)表面分析与元素深度剖析表明, 120℃下在石墨烯表面沉积的Al 2 O 3 薄膜中O和Al元素的含量比约为1.5. 拉曼光谱分析表明, 采用H 2 O-based ALD工艺沉积栅介质薄膜不会降低石墨烯晶体质量.采用水基原子层沉积(H 2 O-based ALD)方法在石墨烯上直接生长Al 2 O 3 介质薄膜, 研究了Al 2 O 3 成核机理. 原子力显微镜(AFM)对Al 2 O 3 薄膜微观形态分析表明, 沉积温度决定着Al 2 O 3 在石墨烯表面的成核生长情况, 物理吸附在石墨烯表面的水分子是Al 2 O 3 成核的关键, 物理吸附水分子的均匀性直接影响Al 2 O 3 薄膜的均匀性. 在适当的温度窗口(100~130℃), Al 2 O 3 可以均匀沉积在石墨烯上, AFM测得Al 2 O 3 薄膜表面均方根粗糙度(RMS)为0.26 nm, X射线光电子能谱(XPS)表面分析与元素深度剖析表明, 120℃下在石墨烯表面沉积的Al 2 O 3 薄膜中O和Al元素的含量比约为1.5. 拉曼光谱分析表明, 采用H 2 O-based ALD工艺沉积栅介质薄膜不会降低石墨烯晶体质量.

Properties of a Ni-FUSI gate formed by the EBV method and one-step RTA

Nickel fully silicided (Ni-FUSI) gate material has been fabricated on a HfO2 surface to form a Ni-FUSI gate/HfO2/Si/Al (MIS) structure by using an ultra-high vacuum e-beam evaporation (EBV) method followed by a one step rapid thermal annealing (RTA) treatment. X-ray diffraction (XRD) and Raman spectroscopy were used to reveal the microstructures and electrical properties of the MIS structure. Results show that a one step post RTA treatment is enough to promote the full reaction of nickel silicide, compared with multiple RTA treatments. Furthermore, the HfO2 gate dielectric film is sensitive to heat treatment, and multiple RTA treatments can damage the electrical properties of the HfO2 film rather than improve them. By optimization of the sample fabrication technique, the MIS capacitor produces good high-frequency capacitance-voltage curves with a hysteresis of 30 mV, a work function of about 5.44–5.53 eV and leakage current density of only 1.45 × 10−8 A/cm2 at −1 V gate bias.