Use of water vapor for suppressing the growth of unstable low-κ interlayer in HfTiO gate-dielectric Ge metal-oxide-semiconductor capacitors with sub-nanometer capacitance equivalent thickness

Annealing of high-permittivity HfTiO gate dielectric on Ge substrate in different gases (N₂, NH₃, NO and N₂O) with or without water vapor is investigated. Analysis by transmission electron microscopy indicates that the four wet anneals can greatly suppress the growth of a GeO_x interlayer at the dielectric/Ge interface, and thus decrease interface states, oxide charges and gate leakage current. Moreover, compared with the wet N₂ anneal, the wet NH₃, NO and N₂O anneals decrease the equivalent permittivity of the gate dielectric due to the growth of a GeO_xN_y interlayer. Among the eight anneals, the wet N₂ anneal produces the best dielectric performance with an equivalent relative permittivity of 35, capacitance equivalent thickness of 0.81 nm, interface-state density of 6.4 × 10¹¹ eV^− 1 cm^− 2 and gate leakage current of 2.7 × 10^− 4 A/cm² at V_g = 1 V.     

Interfacial microstructure of NiSix/HfO2/SiOx/Si gate stacks

Integration of NiSi_x based fully silicided metal gates with HfO₂ high-k gate dielectrics offers promise for further scaling of complementary metal-oxide- semiconductor devices. A combination of high resolution transmission electron microscopy and small probe electron energy loss spectroscopy (EELS) and energy dispersive X-ray analysis has been applied to study interfacial reactions in the undoped gate stack. NiSi was found to be polycrystalline with the grain size decreasing from top to bottom of NiSi_x film. Ni content varies near the NiSi/HfO_x interface whereby both Ni-rich and monosilicide phases were observed. Spatially non-uniform distribution of oxygen along NiSi_x/HfO₂ interface was observed by dark field Scanning Transmission Electron Microscopy and EELS. Interfacial roughness of NiSi_x/HfO_x was found higher than that of poly-Si/HfO₂, likely due to compositional non-uniformity of NiSi_x. No intermixing between Hf, Ni and Si beyond interfacial roughness was observed.     

静电场中介电液体的流体静力学特性及应用

给出静电场和重力场共同作用下介电液体内的压强分布式以及液面高度表达式，并讨论了两个具体问题：用两个平行平板电极间的液面上升高度推求液体的介电常数；分析了Ｓｕｍｏｔｏ效应的成因，并给出其中的液面攀升高度的计算式．     

铌酸盐微晶玻璃的晶化动力学及其储能性能的温度依赖性（英文）

采用熔融-淬冷法制备铌酸锶钡基微晶玻璃材料,研究晶化温度对铌酸锶钡微晶玻璃的显微组织、介电性能、击穿强度和储能密度的影响。微晶玻璃的晶化机理为一维界面晶体生长。结果表明:随着晶化温度的增加,材料的击穿强度明显增加。经900°C热处理得到的微晶玻璃具有最优的性能:击穿强度为1300 kV/cm,储能密度为2.8 J/cm3,其有望用于高储能密度电介质材料。     

Structural and dielectric properties of BaCexTi1-xO3 ceramics

ABSTRACT

In this paper, we prepare silver nanowires circuit graphics by UV-curing technology. The optimal condition of preparation of the silver nanowires circuit graphics are examined. Experiment results show that the UV-curing technology is a kind of individual, low-cost and environment-friendly method to prepare silver nanowires circuit graphics. The main influence factors on the lines' width are the UV beam power and scanning speed. And we also study the influence of the hot pressing temperature on the resistivity of the circuit graphics. In the experiments, the optimal condition is that the UV beam power is 190 mW and the scanning rate is 6 cm/s, then we get the minimum line width, which is 0.25 mm. The thickness of silver nanowires layer is 100 µm and the hot pressing temperature is 100°C, we will get the sample whose resistivity is 21× 10^?5 Ω·cm.     

Wearable temperature sensors based on lanthanum-doped aluminum-oxide dielectrics operating at low-voltage and high-frequency for healthcare monitoring systems

The incorporation of lanthanum (La) into sol-gel based aluminum-oxide (Al₂O₃) dielectrics is investigated by analyzing the dielectric properties obtained from electrical capacitive measurements of metal-insulator-metal. The optimized La doping results in significantly suppressed variation of frequency-dependent capacitance of sol-gel based La-doped Al₂O₃ (LaAlO₃) dielectrics even at high frequencies of ~ MHz. In addition, flexible temperature sensors with sol-gel based LaAlO₃ dielectrics on polyimide substrates are demonstrated through investigations on the capacitive responses to different temperatures ranging from 30 to 200 °C at various frequencies from 100 Hz to 1 MHz. Without any buffer or passivation film, the proposed flexible temperature sensors achieved a high mechanical stability against cyclic bending tests with curvature radii from 10 to 5 mm. Finally, the feasibility of a healthcare monitoring system is demonstrated by utilizing wearable body-temperature sensor arrays consisting of sol-gel based LaAlO₃ dielectrics. High-performance temperature sensor system is capable of analyzing interfacial temperature characteristics on human body between 30 and 40 °C in real-time and displaying them on the use's smartphone. We believe that this study is expected to significantly contribute to the field of wearable bioelectronics consisting of solution-processed metal-oxide dielectrics for healthcare monitoring systems.     

In situ doping of BaTiO3 and visualization of pressure solution in flux-assisted cold sintering

Cold sintering process (CSP) has attracted great interest due to its extremely low processing temperatures, fast processing times, and simplicity to allow for the densification of ceramics and composites. Understanding the detailed mechanisms underlying low temperature densification is crucial to develop advanced materials and facilitate sustainable and cost-effective industrial implementation to come. Here, by taking BaTiO₃ powder and Sr(OH)₂·8H₂O transient chemical flux as a model system, chemical transformation at solid/flux interfaces driving the dissolution-precipitation creep mechanism were investigated. We demonstrate that Sr(OH)₂·8H₂O acts both as a sintering flux and a solid solution doping additive, resulting in the formation of BaTiO₃ - Ba_1-xSr_xTiO₃ with lower Curie temperatures. Using strontium (Sr) as a tracer chemistry, transmission electron microscopy chemical mapping with energy-dispersive X-ray analysis indicates that there is a precipitation of a Ba_1-xSr_xTiO₃ mainly at grain/grain interfaces, while grain cores remain undoped. In addition, the difference in the interfacial Sr concentration, which is influenced by the applied uniaxial pressure direction, was clearly observed. This successful visualization of compositional distribution after CSP underlines the significant role of the pressure solution creep in densification process.     

一种填晶型的隔离介质浆料

在玻璃中加入氧化铝，制成填晶型隔离介质的相对介电常数８～１０，绝缘电阻率大于１０１２Ω·ｃｍ，耐电压强度大于ＡＣ５００Ｖ／２５μｍ，损耗角正切小于５×１０（－３），接近进口同类产品性能指标。     

Structural and interfacial properties of high-k HfOxNy gate dielectric films

The thermal stability and interfacial characteristics for hafnium oxynitride (HfO_xN_y) gate dielectrics formed on Si (1 0 0) by plasma oxidation of sputtered HfN films have been investigated. X-ray diffraction results show that the crystallization temperature of nitrogen-incorporated HfO₂ films increases compared to HfO₂ films. Analyses by X-ray photoelectron spectroscopy confirm the nitrogen incorporation in the as-deposited sample and nitrogen substitution by oxygen in the annealed species. Results of FTIR characterization indicate that the growth of the interfacial SiO₂ layer is suppressed in HfO_xN_y films compared to HfO₂ films annealed in N₂ ambient. The growth mechanism of the interfacial layer is discussed in detail.