Low temperature UV/ozone oxidation formation of HfSiON gate dielectric

Physical and electrical properties of hafnium silicon oxynitride (HfSi_xO_yN_z) dielectric films prepared by UV ozone oxidation of hafnium silicon nitride (HfSiN) followed by annealing to 450 °C are reported. Interfacial layer growth was minimized through room temperature deposition and subsequent ultraviolet/ozone oxidation. The capacitance–voltage (C–V) and current–voltage (I–V) characteristics of the as-deposited and annealed HfSi_xO_yN_z are presented. These 4 nm thick films have a dielectric constant of 8–9 with 12 at.% Hf composition, with a leakage current density of 3×10⁻⁵ A/cm² at V_fb+1 V. The films have a breakdown field strength >10 MV/cm.     

Mechanical properties of glass fiber composites with an epoxy resin modified by a liquid crystalline epoxy

The effect of liquid crystalline networks on epoxy + glass fiber composites is investigated. The matrix obtained from in‐situ curing of liquid crystalline (LC) diglycidyl ether of 4,4‐dihydroxybiphenol (DGE‐DHBP) with diglycidyl ether of bisphenol F (DGEBP‐F) by anhydride curing agent was used as the matrix for polymer composites. Impact, tensile, and flexural testing results are compared between the unmodified and modified systems. The interlaminar fracture toughness of commposites in the shear mode was determined by end notch flexure (ENF) tests. Scanning electron microscopy is used to study the fracture surfaces to understand the mechanism of fracture and interphase formation between the fiber and the matrix.     

Low-temperature deposition of hafnium silicate gate dielectrics

The physical and electrical properties of hafnium silicate (HfSi/sub x/O/sub y/) films produced by low-temperature processing conditions (/spl les/150/spl deg/C) suitable for flexible display applications were studied using sputter deposition and ultra-violet generated ozone treatments. Films with no detectable low-/spl kappa/ interfacial layer were produced. Rutherford backscattering spectroscopy, X-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy were used to determine the composition, chemical bonding environment, thickness, and film interface. The electrical behavior of the as-deposited and annealed hafnium silicate films were determined by current-voltage (I--V) and capacitance-voltage (C--V) measurements.     

Effects of glass fibers and polypropylene/glass fiber hybrid fibers on the kinetics and mechanical properties of epoxy composites

Curing reactions of diglycidyl ether of bisphenol F (DGEBP‐F) and pre‐catalyzed methyltetrahydrophthalic anhydride (MTHPA) with benzyl triethyl ammonium chloride (BTEAC) were studied and effects of glass fibers evaluated. The influence on the kinetics of glass fibers and a hybrid blend of maleated polypropylene + glass fibers is studied. Isothermal and dynamic kinetic parameters are determined by differential scanning calorimetry (DSC). Applicability of the autocatalytic model is investigated. The model serves well in the range of degrees of conversion between 25 and 80%. At high conversion rates the diffusion control becomes apparent. Glass fibers accelerate the curing, shortening the time needed to reach the maximum reaction rate; this is reflected in lower activation energies for curing in comparison to the neat resin. The effects observed can be explained by a reaction between the amine group present on the fiber surfaces and the epoxy glycidyl groups. The result of both isothermal and non‐isothermal curing of resin + glass fibers commingled with polypropylene are close to those for the neat resin. The reinforcement increases the elastic modulus 12 times, the tensile strength 2 times, and the impact strength 285 times. The glass fibers + commingled polypropylene reinforcement provides comparable mechanical properties as glass fibers alone when normalized with respected to the density fraction of the fibers.