• Journal of Radiation Protection and Research
• /
• v.22 no.3
• /
• pp.135-141
• /
• 1997

The study of anneal characteristics is important for TL dosimeter to reuse. To obtain the annealing condition of the recently developed, new TL dosimeter, LiF:Mg,Cu,Na,Si Teflon Tills in a disk type (diameter 4.5 mm, thickness about $90mg/cm^2$), we studied for pre-irradiation annealing, readout procedure and post-readout annealing, in order. The gamma irradiations were carried out with a $^{60}Co$, dose of 0.1 Gy. We have used the method that observe the variation of thermoluminescent(TL) intensity of these Teflon TLDs over repeated cycles by changing both anneal temperature and anneal time with the TLD reader and the oven. There is a 5% loss in sensitivity over the ten repeated readouts by the annealing condition:pre-irradiation annealing at $80^{\circ}C$ for one hour, readout to $280^{\circ}C$ and post-readout annealing at $270^{\circ}C$ for 20 seconds.

• Korean Journal of Materials Research
• /
• v.6 no.12
• /
• pp.1192-1198
• /
• 1996

배선 재료나 salicide 트랜지스터에 적용될 것으로 기대되는 Cu 배선과 Co 단일층 및 Co/Ti 이중층을 사용하여 형성된 코발트 실리사이드간의 열적 안정성에 대하여 조사하였다. 40$0^{\circ}C$열처리후 Cu3Si 막이 CoSi2층과 Si 기판 사이에 형성되었는데, 이것은 Cu 원자의 확산에 기인한 것이다. $600^{\circ}C$에서의 열처리 후에 형성된 최종막의 구조는 각각 Cu/CoSi2/Cu3Si/Si과 TiO2/Co-Ti-Si 합금/CoSi2/Cu3Si/Si였으며, 상부에 형성된 TiO2층은 산소 오염에 의한 것으로 밝혀졌다.

• Journal of Korea Foundry Society
• /
• v.17 no.6
• /
• pp.560-568
• /
• 1997

The dissolution behavior of secondary solidification phases in squeeze cast Al-3.9wt%Cu-1.5wt%Si-1.0wt%Mg has been studied using a combination of optical microscope, image analyzer, scanning electron microscope(SEM), energy dispersive spectrometer(EDS), X-ray diffractometer(XRD) and differential thermal analyzer (DTA). Special emphasis was placed on the investigation of the effects of the nonequilibrium heat treatment on the dissolution of the second solidification phases. Ascast microstructure consisted of primary solidification product of ${\alpha}-Al$ and secondary solidification products of $Al_2Cu$, $Mg_2Si$ and $Al_2CuMg$. Equilibrium and non-equilibrium solution treatments were carried out at the temperatures of $495^{\circ}C$, $502^{\circ}C$ and $515^{\circ}C$ for 3 to 5 hours. The amount of the dissolved secondary phases increased with increasing solution treatment temperature, for example, area fractions of $Al_2Cu$, $Mg_2Si$ and $Al_2CuMg$ were approximately 0%, 1.6% and 4.2% after solution treatment at $495^{\circ}C$ for 5hours, and were approximately 0%, 0.36% and 2% after solution treatment at $515^{\circ}C$ for 5hours. The best combination of tensile properties was obtained when the as-cast alloy was solution treated at $515^{\circ}C$ for 3hours followed by aging at $180^{\circ}C$ for 10 hours. Detailed DTA and TEM study showed that the strengthening behavior during aging was due to enhanced precipitation of the platelet type fine ${\theta}'$ phase.

• Korean Journal of Materials Research
• /
• v.11 no.3
• /
• pp.215-220
• /
• 2001

Amorphous Ti-Si-N films of approximately 200 and 650 thickness were reactively sputtered on Si wafers using a dc magnetron sputtering system at various $N_2$/Ar flow ratios. Their barrier properties between Cu (750 ) and Si were investigated by using sheet resistance measurements, XRD, SEM, RBS, and AES depth profiling focused on the effect of the nitrogen content in Ti-Si-N thin film on the Ti-Si-N barrier properties. As the nitrogen content increases, first the failure temperature tends to increase up to 46 % and then decrease. Barrier failure seems to occur by the diffusion of Cu into the Si substrate to form Cu$_3$Si, since no other X- ray diffraction intensity peak (for example, that for titanium silicide) than Cu and Cu$_3$Si Peaks appears up to 80$0^{\circ}C$. The optimal composition of Ti-Si-N in this study is $Ti_{29}$Si$_{25}$N$_{46}$. The failure temperatures of the $Ti_{29}$Si$_{25}$N$_{465}$ barrier layers 200 and 650 thick are 650 and $700^{\circ}C$, respectively.ely.

• Korean Journal of Materials Research
• /
• v.7 no.6
• /
• pp.498-504
• /
• 1997

Cu는 AI보다 비저항이 더 낮고, 일렉트로마이그레이션 내성이 더 강하기 때문에 AI을 대체하여 사용될 새로운 상부배선 재료로 널리 연구되고 있다. 그러나 Cu는 SiO$_{2}$층을 통해 Si기판 속으로 확산하는 것과 같은 열적불안정성을 갖고 있으므로 Cu 배선을 위해서는 barrier금속을 함께 사용해야 한다. 지금까지 알려진 가장 우수한 재료는 TaSi$_{x}$N$_{y}$이다. Tasi$_{x}$N$_{y}$는 90$0^{\circ}C$에서 불량이 발생하는 것으로 보고된 바 있으나, 그것의 barrier특성과 관련하여 확인하고 또 새로 조사되어야 할 내용들이 많이 있다. 본 연구에서는 반응성 스퍼터링 테크닉을 사용하여 (100)Si 웨이퍼상에 TaSi$_{x}$N$_{y}$막을 증착하고, Cu에 대한 barrier재료로서 반드시 갖추어야 할 열적 안정성을 면저항의측정, X선 회절 및 AES 깊이분석 등에 의하여 조사하였다. 스퍼터링 공정에서 N$_{2}$/Ar기체의 유량비가 15%일때 열적 안정성이 가장 우수한 TaSi$_{x}$N$_{y}$막이 얻어졌다. Ta와 TaN은 각각 $600^{\circ}C$와 $650^{\circ}C$에서 불량이 발생하는 반면, TaSi$_{x}$N$_{y}$는 90$0^{\circ}C$에서 불량이 발생하였다. TaSi$_{x}$N$_{y}$의 불량기구는 다음과 같다:Cu는 TaSi$_{x}$N$_{y}$막을 통과하여 TaSi$_{x}$N$_{y}$/Si계면으로 이동한 다음 Si기판내의 Si원자들과 반응한다. 그 결과 TaSi$_{x}$N$_{y}$Si가 생성된다.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2005.05a
• /
• pp.260-260
• /
• 2005

• Applied Chemistry for Engineering
• /
• v.7 no.2
• /
• pp.261-268
• /
• 1996

Various $Cu/SiO_2$ catalysts with copper concentration ranging from 0 to 50wt% were prepared by kneading method for the steam reforming of methanol. These catalysts were calcined at temperatures in the range of $400^{\circ}C{\sim}900^{\circ}C$ and then reduced in a $H_2$ atmosphere in the range of $150^{\circ}C{\sim}350^{\circ}C$. Steam reforming of methanol was carried out at atmospheric pressure over a temperature range of $200^{\circ}C{\sim}400^{\circ}C$, steam/methanol molar ratio of 0.4~1.6 and W/F of 3~25 g.-cat.hr./mol. Characterization of the catalysts was studied using IR, BET and XRD. Using copper nitrate as a precursor for catalysts, pH in the preparation of catalysts had a great effect on the catalytic activity, but pH in the preparation of catalysts, calcination temperature, and reducing temperature in $H_2$ atmosphere had no effect on the product distribution. Optimum copper concentration, calcination temperature and reducing temperature were 40wt%, $700^{\circ}C$ and $300^{\circ}C$, respective)y. Reaction temperature for maximum $H_2$ production was $275^{\circ}C$, and the formation of methane which lowered quantity and quality of $H_2$ would be inhibited below $275^{\circ}C$. $Cu^{\circ}-Cu_2O$ might be active species in $Cu/SiO_2$ catalyst.

• Proceedings of the KWS Conference
• /
• 1999.05a
• /
• pp.96-97
• /
• 1999

• Proceedings of the Materials Research Society of Korea Conference
• /
• 1999.05a
• /
• pp.144-144
• /
• 1999

• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 2003.04a
• /
• pp.61-62
• /
• 2003