First-principles study of oxygen vacancy in amorphous hafnium silicates = 비정질 하프늄 실리케이트 구조 내에서의 산소 결핍 결함에 관한 제일원리 연구

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In this research, the amorphous phase of $HfSiO_4$ is generated using the molecular dynamics simulation based on the first-principles calculations, and the atomic and electonic structures are investigated. The local bonding structures of the O atoms can be classified as the $SiO_2$-like, mixed, and $HfO_2$-like bonds by the number of Hf and Si atoms in the neighborhood. The bond lengths of Si-O and Hf-O are about 1.66 and 2.14 $\AA$, respectively and the coordination numbers are evaluated to about 4.02, 2.66, and 6.25 for Si, O, and Hf atoms, respectively. O-vacancy in a-$HfSiO_4$ can be also categorized by the number of Hf and Si atoms near the vacancy site : the Si-related, mixed, and Hf-related defects. For the Si- and Hf-related defects, the defect levels are about 0.56 and 2.59 eV, and the formation energies are about 4.89 and 6.12 eV, espectively. From the analysis of the defect levels of O-vacancies, the threshold voltage shift mechanism in p-channel metal-oxide-semiconductor (PMOS) devices can be explained, and the Hf-related defects mainly play the critical role in that mechanism.
Advisors
Chang, Kee-Jooresearcher장기주researcher
Description
한국과학기술원 : 물리학과,
Publisher
한국과학기술원
Issue Date
2009
Identifier
308626/325007  / 020073155
Language
eng
Description

학위논문(석사) - 한국과학기술원 : 물리학과, 2009.2, [ v, 20 p. ]

Keywords

first-principles; amorphous; Hf-silicates; gate oxide; MOS devices; 제일원리; 비정질; 하프늄 실리케이트; 게이트 산화막; MOS 소자

URI
http://hdl.handle.net/10203/48737
Link
http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=308626&flag=dissertation
Appears in Collection
PH-Theses_Master(석사논문)
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