Characterization of Nitrogen-Doped <TEX>$TiO_2$</TEX> Thin Films Prepared by Metalorganic Chemical Vapor Deposition

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J. Korean Ceram. Soc. > Volume 31(12); 1994 > Article

Journal of the Korean Ceramic Society 1994;31(12): 1577.

유기금속 화학 기상증착법으로 실리콘 기판위에 증착된 질소치환 $TiO_2$ 박막의 특성분석

이동헌, 조용수¹, 이월인², 이전국³, 정형진³

²명지대학교 전자공학과
³한국과학기술연구원 세라믹스연구부

Characterization of Nitrogen-Doped $TiO_2$ Thin Films Prepared by Metalorganic Chemical Vapor Deposition

Author to whom correspondence should be addressed
¹NYSCC at Alfred

ABSTRACT

TiO2 thin films with the substitution of oxygen with nitrogen were deposited on silicon substrate by metalorganic chemical vapor deposition (MOCVD) using Ti(OCH(CH3)2)4 (titanium tetraisopropoxide, TTIP) and N2O as source materials. X-ray diffraction (XRD) results indicated that the crystal structure of the deposited thin films was anatase TiO2 with only (101) plane observed at the deposition temperatures of 36$0^{circ}C$ and 38$0^{circ}C$, and with (101) and (200) plane at above 40$0^{circ}C$. Raman spectroscopic results indicated that the crystal structure was anatase TiO2 in accordance with the XRD results without any rutile, fcc TiN, or hcp TiN structure. No fundamental difference was observed with temperature increase, but the peak intensity at 194.5 cm-1 increased with strong intensity at 143.0 cm-1 for all samples. The crystalline size of the films varied from 49.2 nm to 63.9 nm with increasing temperature as determined by slow-scan XRD experiments. The refractive index of the films increased from 2.40 to 2.55 as temperature increased. X-ray photoelectron spectroscopy (XPS) study showed only Ti 2s, Ti 2p, C 1s, O 1s and O 2s peaks at the surface of the film. The composition of the surface was estimated to be TiO1.98 from the quatitative analysis. In the bulk of the film Ti 2s, Ti 2p, O 1s, O 2s, N 1s and N 2s were detected, and Ti-N bonding was observed due to the substitution of oxygen with nitrogen. A satellite structure was observed in the Ti 2p due to the Ti-N bonding, and the composition of titanium nitride was determined to be about TiN1.0 from the position of the binding energy of Ti-N 2p3/2 and the quatitative analysis. The spectrum of Ti 2p energy level could be the sum of a 4, 5, or 6 Gaussian curve reconstruction, and the case of the sum of the 6 Gaussian curve reconstruction was physically most meaningful. From the results of Auger electron spectroscopy (AES), it was known that the composition was not varied significantly throughout the whole thickness of the film, and silicon oxide was not observed at the interface between the film and the substrate. The composition of the film was possible (TiO2)1-x.(TiN)x or TiO2-2xNx and in this experimental condition x was found to be about 0.21-0.16.