자연산화막 존재에 따른 코발트 니켈 복합실리사이드 공정의 안정성

송오성(Song Ohsung),김상엽(Kim, Sang-Yeop),김종률(Kim, Jong-Ryul) 한국산학기술학회 2007 한국산학기술학회논문지 Vol.8 No.1

코발트 니켈 합금형 실리사이드 공정에서 단결정실리콘과 다결정실리콘 가판에 자연산화막이 있는 경우 나노급 두께의 코발트 니켈 합금 금속을 증착하고 실리사이드화하는 경우의 반응 안정성을 확인하였다. 4인치 p-type(100)Si 기판 전변에 poly silicon을 입힌 기판과 single silicon 상태의 두 종류 기판을 준비하고 두께 4㎚의 자연산화막이 있는 상태에서 10㎚ 코발트 니켈 합금을 니켈의 상대조성을 10-90%로 달리하며 열증착하였다. 통상의 600, 700, 800, 900, 1000, 1100℃ 각 온도에서 실리사이드화 열처리를 시행 후 잔류 합금층을 제거하고, XRD(X-ray diffraction)및 FE-SEM(Field emission scanning electron microscopy), AES(Auger electron spectroscopy)를 사용하여 실리사이드가 생겼는지 확인하였다. 마이크로라만 분석기로 실리사이드 반응시의 실리콘 층의 잔류 스트레스도 확인하였다. 자연산화막이 존재하는 경우 실리사이드 반응이 진행되지 않았고, 폴리실리콘 기판과 고온에서는 금속과 산화층의 반응잔류물이 생성되었다. 단결정 기판의 고온열처리에서는 실리사이드 반응이 없더라도 핀홀이 발생할 수 있는 정도의 열스트레스가 존재하였다. 코발트 니켈 복합실리사이드 공정에서는 자연산화막을 제거하는 공정이 필수적이였다. We investigated the silicide reaction stability between 10 ㎚-Col-xNix alloy films and silicon substrates with the existence of 4 ㎚-thick natural oxide layers. We thermally evaporated 10 ㎚-Col-xNix alloy films by varying x=0.1~0.9 on naturally oxidized single crystal and 70 ㎚-thick polycrystalline silicon substrates. The films structures were annealed by rapid thermal annealing (RTA) from 600℃ to 1100℃ for 40 seconds with the purpose of silicidation. After the removal of residual metallic residue with sulfuric acid, the sheet resistance, microstructure, composition, and surface roughness were investigated using a four-point probe, a field emission scanning electron microscope, a field ion beam, an X-ray diffractometer, and an Auger electron depth profiling spectroscope, respectively, to confirm the silicide reaction. The residual stress of silicon substrate was also analyzed using a micro-Raman spectrometer. We report that the silicide reaction does not occur if natural oxides are present. Metallic oxide residues may be present on a polysilicon substrate at high silicidation temperatures. Huge residual stress is possible on a single crystal silicon substrate at high temperature, and these may result in micro-pinholes. Our results imply that the natural oxide layer removal process is of importance to ensure the successful completion of the silicide process with CoNi alloy films.

Electrical Characteristics of Silicide Nanowires and Silicide-induced Grown Si thin Film Solar Cells (초)

김준동,한창수,이응숙 대한금속재료학회 ( 구 대한금속학회 ) 2007 대한금속재료학회 학술대회 개요집 Vol.2007 No.1

Fabrication of Silicide-based Thermoelectric Nanocomposites: A Review

Kim, Gwansik,Kim, Wonkyung,Lee, Wooyoung The Korean Ceramic Society 2019 한국세라믹학회지 Vol.56 No.5

Thermoelectric is a promising technology that can convert temperature differences to electricity (or vice versa). However, their relatively low efficiencies limit their applications to thermoelectric power generation systems. Therefore, low cost and high performance are important prerequisites for the application of thermoelectric materials to automotive thermoelectric generators. Silicide-based thermoelectric materials are good candidates for such applications. Recently, the thermoelectric performances of silicide-based thermoelectric materials have been significantly improved. However, increasing the thermoelectric performance of the materials while ensuring mechanical reliability remains a challenge. This review summarizes the preparation and design guidelines for silicide-based thermoelectric nanocomposites, as well as our recent progress in the development of nanocomposites with high thermoelectric performances or high mechanical reliabilities.

Heavy elemental compound addition enhancing thermoelectric performance of Chromium Silicide synthesized by Spark plasma sintering

Yadav Manju,Upadhyay Naval Kishor,Johari Kishor Kumar,Shyam Radhey,Dhakate Sanjay R.,Gahtori Bhasker,Muthiah Saravanan 한국물리학회 2024 Current Applied Physics Vol.64 No.-

Silicide-based materials drive great potential in developing mid-temperature range thermoelectric generators (TEGs) applications. However, realizing the efficient and stable silicide materials is still a constraint for its real potential device applications. Chromium silicide will likely become p-type thermoelectric materials in this direction for thermoelectric power generation applications. However, high thermal conductivity values impede the figure-of-merit (zT). The present work adopts the chromium silicide, adding different weight percentages of well-known ZrCoSbSn compounds employing the compaction spark plasma sintering (SPS) technique. By adopting these combinations, the thermal conductivity is significantly reduced by enhanced scattering of heat-carrying phonons by multiple interfaces. Also, the maximum power factor value of ≃ 2.1 × 10−3 W/mK2 is achieved by employing a CrSi2 -ZrCoSbSn compound addition. The enhanced figure-of-merit value (zT) ≃ 0.26 is realized in the temperature at 623 K for the CrSi2-5wt% ZrCoSbSn compound material.

Fabrication of Silicide-based Thermoelectric Nanocomposites: A Review

Gwansik Kim,Won Kyung Kim,이우영 한국세라믹학회 2019 한국세라믹학회지 Vol.56 No.5

Thermoelectric is a promising technology that can convert temperature differences to electricity (or vice versa). However, their relatively low efficiencies limit their applications to thermoelectric power generation systems. Therefore, low cost and high performance are important prerequisites for the application of thermoelectric materials to automotive thermoelectric generators. Silicide- based thermoelectric materials are good candidates for such applications. Recently, the thermoelectric performances of silicide-based thermoelectric materials have been significantly improved. However, increasing the thermoelectric performance of the materials while ensuring mechanical reliability remains a challenge. This review summarizes the preparation and design guidelines for silicide-based thermoelectric nanocomposites, as well as our recent progress in the development of nanocomposites with high thermoelectric performances or high mechanical reliabilities.

Tensile properties of a newly developed high-temperature titanium alloy at room temperature and 650 °C

Narayana, P.L.,Kim, Seong-Woong,Hong, Jae-Keun,Reddy, N.S.,Yeom, Jong-Taek Elsevier 2018 Materials science & engineering. properties, micro Vol.718 No.-

<P><B>Abstract</B></P> <P>Commonly used high-temperature near-alpha titanium alloys contain Al, Zr and Si as their alloying elements. Significant losses of mechanical properties and cleavage mode failures are evident due to the presence of Ti3Al and S2 types of zirconium silicides ((TiZr)6Si3) in these alloys. We developed a new alloy (Ti-6.5Al-3.0Sn-4.0Hf-0.2Nb-0.4Mo-0.4Si-0.1B) by replacing Zr with Hf to avoid the formation of zirconium silicides. Aging at 700 °C for five hours successfully eliminated the Ti3Al phase and substantially improved the room-temperature ductility. Tensile tests were carried out at room temperature and at 650 °C. The mechanical properties of the present alloy were significantly improved compared to those of existing high-temperature titanium alloys under testing at ambient and elevated temperatures.</P>

Co-Deposition법을 이용한 Yb Silicide/Si Contact 및 특성 향상에 관한 연구

강준구,나세권,최주윤,이석희,김형섭,이후정 한국진공학회 2013 한국진공학회 학술발표회초록집 Vol.2013 No.2

Properties of Iridium-Inserted Nickel Silicides by Thermal Annealing of the Ni/Ir bilayer on Silicon and Polysilicon Substrates

( Ohsung Song ),( Kijeong Yoon ) 대한금속재료학회 ( 구 대한금속학회 ) 2007 METALS AND MATERIALS International Vol.13 No.3

To improve the thermal stability of the conventional nickel monosilicide, 10 nm-Ni/1 nm-Ir/p-Si(100)(or polycrystalline Si) was thermally annealed using rapid thermal annealing for 40 s at 300-1200 oC. The annealed bilayer structure developed into Ni(Ir)Si, and the resulting changes in sheet resistance, microstructure, and composition were investigated using a four-point probe, a scanning electron microscope, a field ion beam, an X-ray diffractometer, and an Auger electron spectroscope. The final thickness of Ni(Ir)Six formed on single crystal silicon was approximately 40 nm, and it maintained a sheet resistance of below 20 Ω/sq. during the silicidation annealing at 1200 oC. The silicide formed on polysilicon had a thickness of 55 nm, and its low resistance was maintained up to 850 oC. An additional annealing of silicides at 900 oC for 30 min. resulted in a drastic increase in sheet resistance. A possible reason for the improved thermal stability of the silicides formed on single crystal silicon substrate is the role of iridium in preventing NiSi2 transformation. Iridium also improved the thermal stability of the silicides formed on the polysilicon gate, but this enhancement was lessened due to the formation of NiIrSix and also as a result of silicon mixing during high temperature diffusion. In conclusion, the proposed iridium-inserted nickel silicides may be superior to the conventional nickel monosilicides due to improved thermal stability.

Properties of Nickel-Cobalt Composite Silicides by Thermal Annealing of Ni1-xCox ( x = 0.2, 0.5, and 0.8 ) Alloy Thin Films on Silicon and Polysilicon Substrates

( Sangyeob Kim ),( Ohsung Song ) 대한금속재료학회 ( 구 대한금속학회 ) 2007 METALS AND MATERIALS International Vol.13 No.3

10 nm-Ni1-xCox (x = 0.2, 0.5, and 0.8) /p-Si(100)(or poly crystalline Si) was thermally annealed using rapid thermal annealing for 40 s at 600-1100 oC. The annealed film structures developed into NiCoSix, and the resulting changes in sheet resistance, microstructure, and composition were investigated using a four-point probe, a scanning electron microscope, a field ion beam, an X-ray diffractometer, and an Auger electron spectroscope. The final thickness of NiCoSix formed on single-crystal silicon was approximately 12.64 nm, and it maintained its sheet resistance below 20 Ω/sq. during the silicidation annealing at 1100 oC. The NiCoSix formed on polysilicon had a thickness of 35.04 nm, and its low resistance was maintained up to 900 oC. Additional annealing of silicides at the given RTA temperature for 30 min resulted in a drastic increase in sheet resistance. We identified Ni3Si2 and a NiSi phase at 700 oC and 1000 oC for single-crystal silicon substrates. Moreover, Ni3Si2, NiSi, and CoSi2 phases were stable at 700 oC, and then NiSi2 and Ni3Si2 became stable for polycrystalline silicon substrates at 1000 oC. When the amount of Co was 80 %, only a Ni3Si2 phase was confirmed at 700 oC and 1000 oC in both the single and polycrystalline substrates. With less Co (Co = 0.2, 0.5), Ni3Si2, NiSi, and CoSi2 phases were observed at 700 , and Ni3Si2 and NiSi2 phases were observed at 1000 oC. Cobalt also improved thermal stability of the silicides formed on the polysilicon gate, but this enhancement was lessened due to the silicon mixing during high temperature diffusion. In conclusion, the proposed nickel cobalt composite silicides formed from the nano-thick alloy films may be superior to conventional nickel monosilicides due to improved thermal stability.

폴리실리콘 기판 위에 형성된 코발트 니켈 복합실리사이드 박막의 열처리 온도에 따른 물성과 미세구조변화

김상엽,송오성,Kim, Sang-Yeob,Song, Oh-Sung 한국재료학회 2006 한국재료학회지 Vol.16 No.9

Silicides have been required to be below 40 nm-thick and to have low contact resistance without agglomeration at high silicidation temperature. We fabricated composite silicide layers on the wafers from Ni(20 nm)/Co(20 nm)/poly-Si(70 nm) structure by rapid thermal annealing of $700{\sim}1100^{\circ}C$ for 40 seconds. The sheet resistance, surface composition, cross-sectional microstructure, and surface roughness were investigated by a four point probe, a X-ray diffractometer, an Auger electron spectroscopy, a field emission scanning electron microscope, and a scanning probe microscope, respectively. The sheet resistance increased abruptly while thickness decreased as silicidation temperature increased. We propose that the fast metal diffusion along the silicon grain boundary lead to the poly silicon mixing and inversion. Our results imply that we may consider the serious thermal instability in designing and process for the sub-0.1 um CMOS devices.