The effects of B 2 O 3 addition on the sintering behavior and the dielectric and ferroelectric properties of Ba 0.7 Sr 0.3 TiO 3 (BST) ceramics were investigated. The dielectric and ferroelectric properties of a BST sample with 0.5 wt% B 2 O 3 sintered at <1150°C were as good as those of undoped BST sintered at 1350°C, and the dielectric loss was better. When >1.0 wt% B 2 O 3 was added to BST, the overdoped B 2 O 3 did not form a liquid phase or volatilize; it remained in the samples and formed a secondary phase that lowered the sintering behavior and the dielectric and ferroelectric properties of the BST.
The authors review and extend analytic, numerical and experimental work on the capacitance, C(f), and dielectric breakdown field, Eb(f), of a simple insulator containing volume fraction, f, of randomly located metal inclusions. In the case of spherical inclusions, they find Eb(f)=Eb(0)/(1+kc(ln V/ mod ln f mod )alpha ). V is the sample volume divided by the average volume of an inclusion, kc is a constant and 1/2< alpha <1 for large ln V/ mod ln f mod . In the dilute inclusion limit, the statistics of the dielectric breakdown field are shown to be of a modified Gumbel form. The scaling theory of capacitance in composites with percolation microstructures is outlined, and the authors discuss extensions to include hard core repulsion between inclusions. They have fabricated many samples of paraffin wax (a simple insulator) containing various concentrations of stainless-steel spheres (size range 10-65 mu m). The capacitance and dielectric breakdown field of these samples is presented and the results are compared with theory.
The effects of heating rate on the sintering behavior and the dielectric properties of Ba 0.7 Sr 0.3 TiO 3 ceramics prepared by boron-containing liquid-phase sintering were investigated. When 0.5 wt% B 2 O 3 was added to Ba 0.7 Sr 0.3 TiO 3 , sintering was achieved at ϳ1150°C, and the overdoped B 2 O 3 did not form an adequate amount of liquid phase or volatilize; it remained in the samples and formed a secondary phase. A transition broadening was observed as the heating rate increased. As the heating rate increased, the Curie temperature increased and the maximum dielectric constant (k max ) at the Curie temperature decreased. This result is attributable to a decrease in the diffuseness parameter (␦) and the tetragonality (c/a).
It is necessary to have more appropriate resist parameters in order for a lithography simulator to predict real photoresist profiles. These process parameters are usually obtained by flood exposure experiments without pattern masks. However, real processes are performed with pattern masks. Since the intensity on the wafer is different with and without a pattern, the development parameters must be modified in order to predict real processes. Especially, the development parameters, one example of the process parameters, are crucial to mimic real processes. It has been reported that the development parameters of a photoresist with or without underlying patterns are different. In this paper, we modified the flood exposure development parameters of a 248-nm chemically amplified resist (CAR) to get patterned development parameters and compared them with the simulation results. First, we obtained the development parameters by using a flood exposure experiment and applied them to our lithography simulator LUV. The simulated resist profiles were then compared to SEM microphotographs. Second, we modified the development parameters for the simulated resist profile to match the SEM photographs. We also determined the relationship between the changes of the parameters and the pattern profile. We could see the effect of the modification in different line widths and sidewall angle.
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