Hyo-Soon Shin

The Strength of Material with the Amount and the Particle Size of Glass on Anorthite System for LTCC

Among LTCC material for substrate, the crystallized anorthite system was mainly studied as high strength material. However, specific factors that have affected on strength of material were studied insufficiently on anorthite system. In this study, the composition of anorthite glass was Ca-Al-Si-Zn-O. The changes of phase and microstructure were observed with the amount and the particle size of glass and the sintering temperature. It was studied that the factors affected on the strength of material. Phases of anorthite and were formed with the increase of sintering temperature. The phase was increased with amount, acted as filler, and the strength of material is increased with phase. But phases of anorthite and didn`t affect on the strength of material. In the case of 60 vol% glass amounts and below of glass particle size, the strength of material was decreased. It is thought that the decrease of strength was due to non-homogeneous mixing between glass powder and filler.

Sintering and Dielectric Properties in Cordierite/Glass Composite for LTCC Application

Recently, there has been growing interest in low loss and low dielectric constant material for LTCC application, as the frequency range for electronic devices increases. This study was designed to evaluate the effect of cordierite filler for low dielectric constant LTCC material. From the previous experiments, two glass compositions of B-Si-Al-Zn-Ba-Ca-O and B-Si-Al-Sr-Ca-O system, were chosen. Each powder of two glass compositions was sintered respectively with commercial cordierite powder in temperature range from . Crystalline cordierite and glass peaks were affected only with two factors of composition and sintering temperature among various factors. With the optimized condition of two cordierite/glass compositions, obtained dielectric constant was below 5.5 and quality factor was above 1,000. Closed pore of sintered body was controled by sintering temperature and sintering time. When cordierite/glass composite with ratio of 5.5:4.5 was sintered at , densification was sufficient with good dielectric characteristics of

Electrical Properties of ZnO-Bi 2 O 3 -Sb 2 O 3 Ceramics

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Sintering and Electrical Properties of Mn-doped ZnO-TeO 2 Ceramics

In this study, it has been investigated on the changing behavior of electrical properties in (Sb/Bi

Sintering and Electrical Properties of Ni-doped ZnO-Bi 2 O 3 -Sb 2 O 3

We investigated the sintering and electric properties of ZnO-1.0 at% (ZT1) and 1.0 at% Mn-doped ZT1(ZT1M1) system. itself melts at in air but forms the or phase with ZnO as increasing temperature and therefore retards the densification of ZnO to . In ZT1M1 system, also, the densification of ZnO was retarded up to and then reached > 90% of theoretical density above . It was found that a good varistor characteristics(nonlinear coefficient ) were developed in ZT1M1 system sintered at due to Mn which known as improving the nonlinearity of ZnO varistors. The results of C-V characteristics such as barrier height (), donor density (), depletion layer (W), and interface state density () in ZT1M1 ceramics were , 1.6 V, 93 nm, and , respectively. Also we measured the resistance and capacitance of grain boundaries with temperature using impedance and electric modulus spectroscopy. It will be discussed about the stability and homogeneity of grain boundaries using distribution parameter () simulated with the Z(T)-logf plots.

Defects and Grain Boundary Properties of Cr-doped ZnO

The present study aims at the examination of the effects of 1 mol% NiO addition on the reaction, microstructure development, resultant electrical properties, and especially the bulk trap and interface state levels of (Sb/Bi

Evaluation and Optimization of Dispersion in Slurry Preparation of Commercial LTCC Material

In this study, we investigated the effects of Cr dopant (1.0 at% sintered at for 1 h in air) on the bulk trap (i.e. defect) and interface state levels of ZnO using dielectric functions (, , , , and ), admittance spectroscopy (AS), and impedance-modulus spectroscopy (IS & MS). For the identification of the bulk trap levels, we examine the zero-biased admittance spectroscopy and dielectric functions as a function of frequency and temperature. Impedance and electric modulus spectroscopy is a powerful technique to characterize grain boundaries of electronic ceramic materials as well. As a result, three kinds of bulk defect trap levels were found below the conduction band edge of ZnO in 1.0 at% Cr-doped ZnO (Cr-ZnO) as 0.11 eV, 0.21 eV, and 0.31 eV. The overlapped defect levels ( and ) in admittance spectra were successfully separated by the combination of dielectric function such as , , and . In Cr-ZnO, the interfacial state level was about 1.17 eV by IS and MS. Also we measured the resistance () and capacitance () of grain boundaries with temperature using impedance-modulus spectroscopy. It have discussed about the stability and homogeneity of grain boundaries using distribution parameter () simulated with the Z-logf plots with temperature.

Bonding of Different Mate using Common Glass in Zero Shrinkage LTCC

Laminated LTCC components of high integrity, fabricated by thick film process, are applied to industrial field of IT technology along with miniaturization trend of electronic devices. Dispersion states were examined by several evaluation methods with MLS-22, which is one of commercial LTCC powders, to achieve optimal dispersion as basis for stable LTCC fabrication process. Slurry viscosity, surface roughness of dip-coated slide glass, sedimentaion of slurry, and SEM observation of dried surface were utilized with respective amount change of various commercial dispersants. Among these commercial dispersants, optimal dispersion state was obtained with 0.4 wt% of BYK-111, from the results of various evaluation methods.

Effect of Binder Content on Physical Properties of LTCC Green Tapes

To improve warpage, delamination and the chemical reaction between 2 different co-fired materials, the bonding behavior with common glass was studied. As shown in the previous paper, the phenomenon of the infiltration is different with the composition of the glass. In particular, in the case of low temperature melting glass, infiltration is experimented in this study. GA-1 glass is infiltrated among particles below and is made by glass/ceramic composite. Until the laminate is fired under , provskite phase is observed. Although in the case of GA-12 glass, the temperature of the glass infiltration is lower than it of GA-l glass, the perovskite phase already disappears at . As a result, GA-1 and GA-12 glasses are infiltrated among particles at low temperature, however, the chemical reactivity of the glass/ceramic and sintering temperature should be considered.

Characteristics of a NOx Gas Sensor based on a Low-Temperature Co-Fired Ceramic and Ga-Doped ZnO

The properties of LTCC green tape with addition of binder were investigated in order to understand an effects of binder on multilayer processing. A green sheet form was fabricated through tape casting method with the MLS-22 powder. The lamination density increased with increasing amount of binder and lamination pressure. With increasing amount of binder, the elongation of ceramic sheets increased but the tensile stress and air-permeability decreased. The addition of excessive binder is caused defects in the green sheet during via hole punching. The optimum condition of the via hole without defects was observed from amount of the binder 10 wt%.