• 한국세라믹학회지
• /
• 제30권6호
• /
• pp.510-516
• /
• 1993

$PbTiO_3$ thin films have been formed by rapid thermal annealing(RTA) of $TiO_2$/Pb/$TiO_2$ multilayer films deposited on Si wafers by RF sputtering. Based on the optimal depositon conditions of TiO2 and Pb, $TiO_2$/Pb/$TiO_2$ three layers were deposited for 900$\AA$ each. These films were subjected to RTA process at the temperatures ranging from $400^{\circ}C$ to $900^{\circ}C$ for 30 seconds in air, and were analyzed by X-ray diffraction and transmission electron microscopy to investigate the phases and the microstructures. As a result, perovskite $PbTiO_3$ phases was obtained above $500^{\circ}C$ with the trace of unreacted $TiO_2$. RBS analysis revealed the anisotropic behavior of diffusion that the diffusivity of Pb to the bottom $TiO_2$ layer was faster than that of Pb to the top $TiO_2$ layer. The amorphous Pb-silicate was formed between film and Si substrate due to the diffusion of Pb, but Pb-silicate existed locally at the interface and the amount of that phase was very small. Therefore the effect of bottom $TiO_2$ layer as a diffusion barrier was confirmed. $PbTiO_3$ films formed by current technique showed a relative dielectric constant of 60, and the maximum breakdown field reached 170kV/cm.

• Environmental Engineering Research
• /
• 제10권3호
• /
• pp.112-121
• /
• 2005

The effectiveness of quicklime-based stabilization/solidification (S/S) in immobilizing lead (Pb) was assessed by performing semi-dynamic leaching tests (ANS16.1). In order to simulate landfill leaching conditions, the ANS 16.1 test was modified by using 0.014 N acetic acid (pH = 3.25) instead of distilled water. Artificial soil samples as well as field soil samples contaminated with Pb were tested. The effectiveness of quicklime treatment was evaluated by determining diffusion coefficients ($D_e$) and leachability indices (LX). A model developed by de Groot and van der Sloat was used to elucidate the controlling Pb leaching mechanisms. Overall, upon quicklime treatment Pb leachability was significantly reduced in a]l of the samples tested. The mean LX values were higher than 9 for an artificial soil sample containing 30% kaolinite treated with 10% quicklime and for a field soil sample treated with 10% quicklime, which suggests that S/S treated soils can be considered acceptable for "controlled utilization". Moreover, quicklime treatment was more effective in artificially contaminated soil with high kaolinite content (30%), indicating the amount of clay plays an important role in the success of the treatment. The controlling Pb leaching mechanism was found to be diffusion, in all quicklime treated samples.

• 마이크로전자및패키징학회지
• /
• 제13권1호통권38호
• /
• pp.7-15
• /
• 2006

63Sn-37Pb 솔더의 실시간 electromigration 거동 관찰을 박막형 edge 이동 선형시편과 주사전자현미경을 이용하여 실시하였다. 공정조성 63Sn-37Pb 솔더의 electromigration에 의한 edge 이동 잠복기는 $90{\sim}110^{\circ}C$에서 뚜렷하게 존재하였다. 온도에 따른 electromigration 우선확산원소는 실험온도 $90{\sim}110^{\circ}C$에서 Pb, $25{\sim}50^{\circ}C$에서는 Sn으로 나타났고, $70^{\circ]C$에서는 Sn과 Pb가 거의 동시에 이동하여 우선확산 원소가 관찰되지 않았다. $90{\sim}110^{\circ}C$에서 관찰된 SnPb의 electromigration에 의한 edge 이동 잠복기는 Pb 우선이동에 의해 발생되었다. 이러한 edge 이동 잠복기의 존재는 플립칩 (flip chip) 솔더범프의 수명과 밀접한 관계를 가지는 것으로 보인다. Electromigration에 의해 발생되는 SnPb 솔더의 우선확산원소의 온도 의존성은 Pb와 Sn의 확산계수와 함께 $Z^*$ (전기장내의 유효전하 수)도 크게 영향을 미치는 것으로 생각된다.

• Journal of Electrochemical Science and Technology
• /
• 제2권2호
• /
• pp.76-84
• /
• 2011

Potentiostatic oxidation of Pb-1.7%Sb alloy used in the manufacture of grids of lead-acid batteries over the potential range from -1.0V to 2.3V in 5M $H_2SO_4$ in the absence and the presence of 0.4M $H_3PO_4$ and the self-discharge characteristics of the oxide layer formed is studied by electrochemical impedance spectroscopy (EIS). Depending on the potential value, sharp variations in resistance and capacitance of the alloy are recorded during the oxidation and they can be used for identification of the various substances involved in passive layer. Addition of $H_3PO_4$ is found to deteriorate the insulating properties of the passive layer by the retardation of the formation of $PbSO_4$. $H_3PO_4$ completely inhibits the current and impedance fluctuations recorded in $H_3PO_4$-free solutions in the potential range 0.5 V-1.7 V. These fluctuations are attributed to the occurrence of competitive redox processes that involve the formation of $PbSO_4$, $PbOSO_4$, PbO and $PbO_2$ and the repeated formation and breakdown of the passive layer. Self-discharge experiments indicate that the amount of $PbO_2$ formed in the presence of $H_3PO_4$ is lesser than in the $H_3PO_4$-free solutions. The start of transformation of $PbSO_4$ into $PbO_2$ is greatly shortened. $H_3PO_4$ facilitates the diffusion process of soluble species through the passive layer ($PbSO_4$ and basic $PbSO_4$) but impedes the diffusion process through $PbO_2$.

• 한국결정성장학회지
• /
• 제8권2호
• /
• pp.307-314
• /
• 1998

졸-겔법을 이용하여 PZT박막을 제조하였다. 출발물질로는 Pb-acetate trihydrate, Zr-normal propoxide와 Ti-ispropoxide를 사용하였으며, 용매로는 2-Methoxyethanol과 iso- Propanol을 사용하였다. 기판에 따른 Pb 이온 및 Si 이온의 확산을 고찰하기 위해 bare Si와 열산화된 $SiO_2/Si$ 그리고 산화된 기판 위에 졸-겔 spin-coating법으로 $TiO_2$를 입힌 $TiO_2/SiO_2/Si$ 기판을 사용하였다. 박막의 치밀화 및 기판과의 접착상태는 SEM을 이용하였고, 상생성 온도는 XRD, 그리고 Pb 이온 및 Si 이온의 확산 정도는 ESCA를 사용하였다. 기판으로 bare Si 및 $SiO_2/Si$를 사용한 경우, $700^{\circ}C$에서 perovskite상을 얻을 수 있었으며, SiO2/Si 기판을 사용하여 Si의 막으로의 확산을 다소 방지할 수 있었다. $TiO_2/SiO_2/Si$기판을 사용한 경우, $500^{\circ}C$에서 perovskite상을 얻을 수 있었고, Pb 이온 및 Si 이온의 확산을 방지할 수 있었다.

• Journal of Welding and Joining
• /
• 제19권3호
• /
• pp.311-316
• /
• 2001

This paper presents that the affecting factors to the solderability and initial reliability. It is the factor that the coefficient of thermal expansion between package and PCB(Printed Circuit Board), the quantity of solder paste and reflow condition, and Au thickness of the solder ball pad on polyimide tape. As the reflow soldering condition for 48 ${\mu}BGA$ is changed, it is estimated that the quantity of Au diffusion at eutectic Sn-Pb solder surface and initial bonding strength of eutectic Sn-Pb solder and lead free solder. It is the result that quantitative measurement of Au diffusion quantity is difficult, but the shear strength of eutectic Sn-Pb solder joint is 842 mN at first reflow and increases 879 mN at third reflow. The major failure mode in solder is judged solder fracture. So, Au diffusion quantity is more affected by reflow temperature than by the reflow times.

• 대한전기학회논문지
• /
• 제43권5호
• /
• pp.795-801
• /
• 1994

The BiPbSrCaCuO superconductor was fabricated by diffusion of The dual layer composed of SrS12TCaS11TCuS12TOS1xT in upper layer and BiS12TPbSI0.3TCuS12TOS1yT in lower layer, and varified growh-mechanism of BiPbSrCaCuO superconducting phase. And, we produced optimum conditions of spread volume and each stage of sintering time were upper layer:Lower layer=1:0.2, 1:0.4, 1:0.6 and 24hr., 120hr., 210hr. From the result, the optimum conditions are spread volume(Upper layer:Lower layer=1:0.6), sintering time(210hrs.) at 820$^{\circ}C$.The BiPbSrCaCuO superconductor, fabricated optimum condition, showed zero resistance at critical temperature of 70k.

• 한국세라믹학회지
• /
• 제37권1호
• /
• pp.102-109
• /
• 2000

When PbZrO3 (PZ) and PbTiO3 (PT) particles were scattered on polished surfaces of sintered Pb(Zr0.52Ti0.48)O3 (PZT; Zr/Ti=1.08) and then annealed, the PZT grain boundaries migrated. Near the scattered particles, grain boundaries were corrugated and thus the grain shape changed from a normal one to irregular ones. Especially, near the scattered PZ particles, fast grain growth occurred. In the regions swept by moving grain boundaries, the Zr/Tiratio was measured to be about 1.35 for of PZ scattering and about 0.8 for PT scattering, respectively. This result indicates that the grain boundary migration was induced by alloying of Zr and Ti ions in PZT grains, as in usual diffusion induced grain boundary migration(DIGM). A calculation showed that higher coherency strain energy was induced for PT scattering because of higher alloying of Ti than of Zr.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2002년도 추계학술대회 논문집 Vol.15
• /
• pp.546-547
• /
• 2002

Ni thin film on the PMN-PT crystal wafer were deposited by using E-beam evaporator technique. Deposited film was patterned by UV-lithography and etching and was in-diffused at 300~600C. Diffusion profile of Ni ions in PMN-PT was measured by secondary ion mass spectroscopy (SIMS).

• E2M - 전기 전자와 첨단 소재
• /
• 제9권10호
• /
• pp.991-1000
• /
• 1996

PbTiO$_{3}$-PbZrO$_{3}$-Pb(Ni$_{1}$3/Nb$_{2}$3/O$_{3}$) (PZT-PNN) thin films were prepared from corresponding metal organics partially stabilized with diethanolamine by the sol-gel spin coating method. Each mol ratio of PT:PZ:PNN solutions were #1(50:40:10), #2(50:30:20), #3(45:35:20), #4(40:40:20), #5(40:50:10), #6(35:45:20) and #7(30:50:20) respectively. The spin-coated PZT-PNN films were heat-treated at 350.deg. C for decomposition of residual organics, and were sintered from 450.deg. C to 750.deg. C for crystallization. The substrates, such as Pt and Pt/TiN/Ti/TiN/Si were used for the spin coating of PZT PNN films. The perovskite phase was observed in the PZT-PNN films heat-treated at 500.deg. C. The crystalline of the PZT-PNN films was optimized at the sintering of 700.deg. C. By the result of AES analysis, It is confirmed that the films of TiN/Ti/TiN was a good diffusion barrier and that co-diffusion into the each films was not observed.