Silicon carbide is considered to be a potentially useful material for high-temperature electronic devices, as the p-type and/or n-type conduction can be controlled by impurity doping. Particularly, electric conductivity of the porous n-type SiC semiconductor fabricated from β-SiC powder at 2000℃ was comparable to or even larger than the reported value of SiC single crystal in the high-temperature region, while thermal conductivity was kept as low as 1/10 to 1/30 of that for a dense SiC ceramics. In this work, for the purpose of decreasing sintering temperature, it was attempted to fabricate the porous reaction-sintered bodies at low temperatures(1500-1600℃) by thermal decomposition of polycarbosilane(PCS) impregnated in p-type β-SiC powder. The impregnation and re-sintering process resulted in a improvement in electrical conductivity and the Seebeck coefficient. However the power factor which reflects the thermoelectric conversion efficiency of the present work is slightly lower than that of the porous p-type α-SiC semiconductor fabricated by conventional sintering at 2000℃, it can be stated that thermoelectric properties of SiC semiconductor fabricated by the present reaction-sintering process could be further improved by precise control of the carrier density of the starting material p-type β-SiC, compaction pressure, impregnation and re-sintering process.
한국어
SiC는 불순물 고용에 의해 p형 및 n형 전도의 제어가 용이해서 고온용 전자부품소재로 활용이 가능한 재 료이다. 특히 2000℃에서 제작한 다공질 n형 β-SiC 반도체의 경우, 고온에서의 도전율 값이 단결정 SiC와 비교해서 비슷하거나 오히려 높은 값을 나타내었으며, 반면에 열전도율은 치밀한 SiC 세라믹스와 비교시 1/10∼1/30 정도로 낮은 값을 나타내었다. 본 연구에서는 SiC의 소결온도를 낮추기 위해 p형 β-SiC에 함침 시킨 Polycarbosilane(PCS) 의 열분해에 의한 반응소결 공정(1500~1600℃)으로 다공질 소결체를 제작하였다. 함침 및 재소결 공정에 의해 도 전율과 Seebeck 계수가 증가하였고, 열전변환 효율을 반영하는 Power Factor는 2000℃에서 상압소결 공정으로 제작한 다공질 p형 α-SiC 반도체에 비해 다소 작게 나타났지만, 출발시료인 p형 β-SiC 분말의 캐리어농도, 성형 압력, PCS 함침조건 및 재소결 등의 세밀한 제어를 통해 반응소결 공정으로 제작한 SiC 반도체의 열전물성은 크 게 향상될 것으로 판단된다.
목차
요약 Abstract Ⅰ. 서론 Ⅱ. 실험 2.1 시료 준비 및 분석 2.2 열전 물성 측정 Ⅲ. 결과 및 고찰 3.1 반응소결 3.2 도전율 3.3 Seebeck 계수 3.4 Power Factor Ⅳ. 결론 REFERENCES
Ever since next generation convergence technology became one of the most important industries in the nation, computing professionals have encountered a growing number of challenges. Along with scholars and colleagues in related fields, they have gathered in avariety of forums and meetings over the last few decades to share their knowledge, experiences and the outcome of their research. These exchanges have led to the founding of the International Next-generation Convergence technology (INCA) on December 1, 2015. INCA was registered as an incorporated association under the Ministry of Information and Communications. The main purpose of the organization is to improve our society by achieving the highest capability possible in next generation convergence technology.
간행물
간행물명
차세대융합기술학회논문지 [The Journal of Next-generation Convergence Technology Association]