서지주요정보
Cr-Al-O-N 시스템의 전자상태 전산모사 및 측정 = Electronic structure calculation and spectroscopic analysis of Cr-Al-O-N systems
서명 / 저자 Cr-Al-O-N 시스템의 전자상태 전산모사 및 측정 = Electronic structure calculation and spectroscopic analysis of Cr-Al-O-N systems / 최영민.
저자명 최영민 ; Choi, Young-Min
발행사항 [대전 : 한국과학기술원, 2003].
Online Access 원문보기 원문인쇄

소장정보

등록번호

8014371

소장위치/청구기호

학술문화관(문화관) 보존서고

DMS 03027

SMS전송

도서상태

이용가능

대출가능

반납예정일

초록정보

A phase-shifting mask (PSM) is expected to enhance optical lithography in the very large-scale integrated/very-high-speed-integrated-circuit era. PSM changes the phase of light to cause destructive interference at the edge with an original light. The use of PSM improves both resolution and depth of focus without significantly altering the existing exposure system. In order to acquire the resolution for deep-ultraviolet (DUV) lithography, it requires proper transmittance and transmittance slope at the energy of light source in inspection and lithography process. Chromium aluminum oxide has been proposed as a candidate material for PSM in DUV optical lithography, but it is difficult to meet the requirements of transmittance slope using chromium aluminum oxide. When nitrogen is substituted for oxygen in Cr-Al-O system, it shows a proper transmittance slope through the control of composition, thickness, etc. Such optical properties are closely related to the electronic structure of material. Accordingly, understanding the electronic structure of chromium aluminum oxynitride is important to develop the mask material. The electronic structure of chromium aluminum oxide and oxynitride is investigated theoretically and experimentally. The electronic structure is calculated and compared with the results of photoelectron spectroscopy such as X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). Lattice simulation (LS) and molecular dynamics (MD) are used to determine atomic structure of crystalline and amorphous phase. Then the embedded cluster model within the framework of discrete variational (DV)-Xα method is employed to investigate the electronic structure of their optimized structures. The several model clusters, formulated with different atomic concentration, are chosen to simulate atomic structures in both crystalline and amorphous phase. Simulation is verified by comparing calculated partial density of states (PDOS) with the results of photoelectron spectroscopy. PDOS, which calculated by DV-Xα method with embedded cluster model, is well consistent with photoelectron spectra of chromium aluminum oxide and chromium aluminum oxynitride systems. In chromium aluminum oxide system, valence band consists of O 2p orbital that is the highest occupied molecular orbital (HOMO). Lowest unoccupied molecular orbital (LUMO) is partially unoccupied Cr 3d. Band gap, defined as the difference between LUMO and HOMO level, increases slowly from 4.01 to 6.09 eV with the concentration of aluminum oxide below 0.9 mole fraction. As the composition close to pure aluminum oxide, band gap increases abruptly to the band gap of pure aluminum oxide (∼10 eV). When nitrogen is substituted for oxygen in Cr-Al-O system, N 2p level appears between O 2p and Cr 3d level. So the valence band of chromium aluminum oxynitride becomes broader and the band gap becomes smaller than that of chromium aluminum oxide. This N 2p orbital should closely relate to the transmittance slope in Cr-Al-O-N systems. In order to verify the valence band structure precisely, valence band photoemission experiments were carried out at 4B1 beam line of Pohang Light Source. The results shows that the valence band of Cr-Al-O-N system was consisted of partially occupied Cr 3d and N 2p orbital in the energy region of 0-7 eV. The electronic structure of chromium aluminum oxide and oxynitride can be elucidated for PSM application through the theoretical calculation in quantum scale and experimental verification.

서지기타정보

서지기타정보
청구기호 {DMS 03027
형태사항 xii, 157 p. : 삽도 ; 26 cm
언어 한국어
일반주기 저자명의 영문표기 : Young-Min Choi
지도교수의 한글표기 : 노광수
지도교수의 영문표기 : Kwang-Soo No
수록잡지명 : "Electronic structure simulation of chromium aluminum oxynitride by discrete variational-Xa method and X-ray photoelectron spectroscopy". Japanese journal of applied physics, v.41 no.9, pp. 5805-5808 (2002)
학위논문 학위논문(박사) - 한국과학기술원 : 재료공학과,
서지주기 참고문헌 : p. 153-157
주제 전자상태 전산모사 및 측정
크롬알루미늄계 위상변위마스크
DV-Xa법
분자동력학
광전자 분광분석
Electronic structure calculation and spectroscopic analysis
Chromium aluminum oxynitride
DV-Xa method
Molecular dynamics
Photoemission spectroscopy
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