서지주요정보
실리콘 기판 위에 졸겔 스핀 코팅법으로 제조된 티탄산연 박막의 미세 구조 및 결정화에 대한 고찰 = Microstructural and crystallizational aspects of sol gel spin coated lead titanate thin films on a silicon substrate
서명 / 저자 실리콘 기판 위에 졸겔 스핀 코팅법으로 제조된 티탄산연 박막의 미세 구조 및 결정화에 대한 고찰 = Microstructural and crystallizational aspects of sol gel spin coated lead titanate thin films on a silicon substrate / 이전국.
저자명 이전국 ; Lee, Jeon-Kook
발행사항 [대전 : 한국과학기술원, 1991
Online Access 원문보기 원문인쇄

소장정보

등록번호

8001679

소장위치/청구기호

학술문화관(문화관) 보존서고

DMS 9109

휴대폰 전송

도서상태

이용가능

대출가능

반납예정일

초록정보

Sol-gel processing provides an interesting alternative method for the fabrication of thin ferroelectric layers which is useful in nonvolatile memory devices applications. Much of the recent sol-gel ferroelectric thin film research has been directed at the PbO based perovskite compounds such as $PbTiO_3$, PZT. The microstructure and crystallization and C-V characteristics of lead titanite thin films an a silicon substrate were highly dependent on the sol-gel processing methods, the substrate materials, film thickness, heat heating conditions. So, in this study, we found optinum conditions to fabricate high quality dried gel films. When dried gel films were heat treated, microstructural and crystallizational aspects of lead titanate thickness and solution catalyst were also considered. The solution formed should have a high concentration of the necessary components and be stable under ambient conditions. With these considerations, lead acetate trihydrate and titanium isopropoxide in methoxyethanol were used as precursor materials. The lead acetate solution was dehydrated by successive distillations, until the new distillate was anhydrous. Stock solutions were formed by combining the lead and titanium precursor solutions. Thin films were cast on polished (100) single crystal silicon wafer at 3000r.p.m. using a photoresist spinner. Coating solutions were syrigned through in-line filters directly onto the substrates in clean-room conditions(25℃, 50% relative humidity, class 100) Lead acetate trihydrates were partly methoxyethylated and trihydrates were partly nemoved (about 70%). Titanium isopropoxide underwent complete transesterifications by methoxyethanol. Pb. Ti complex alkoxide were formed by mixing Pb precursor and Ti precursor, and stable for coating in 1 molar concentration. Using coating solution(0.5 molar concentration, $R_w=2$, viscosity 1 cps), Crack free and uniform dried gel films with thickness of 0.2㎛ were formed by coating conditions (temp. 25℃, 50% relative humidity, class 100 clean bench, 3000 r.p.m.)and rapid drying (at 215℃, for 5min). Dried gel films with thickness of 0.36㎛ could be heat treated(heating rate 0.5℃/min.) at 500℃ for 60min. to make crack free lead titanate films. But dried gel films with thickness of 0.68㎛ were cracked by same heat treatment. So, drying and heat treating conditions should be improved. Uncatalyzed dried-gel films with thickness of 0.12㎛ were crystallized to perovskite structures by heat treatment above 600℃ Heat treated films were inhomogeneous in microstructures, with flat band voltage(in capacitance voltage plot) and dielectric constant of 0.10V and 8.5, respectively. But 0.1M nitric acid catalyzed dried-gel films were crystallized to pyrochlore structures by heat treatment above 500℃. Heat treated (at 600℃) films were homogeneous in microstructures, with flat band voltage of -0.40V. It means that films are stable in oxide semiconductor structures. Dielectric constant was decreased to 2.8 because of difference in crystal structures. Dried gel films with thickness of 0.36㎛ were crystallized to anisotropic perovskit structures by heat treatment above 500℃ regardless of catalyzing. Uncatalyzed films heat treated at 600℃ for 60min. were inhomogeneous in microstructure, with c/a ratio in perovskite structure, flat band voltage, and dielectric constant of 1.046, 0.75V, and 33, respectively. But in case of 0.1M nitric acid catalyzed films, heat treated films were homogeneous in microstructure, with c/a ratio, flat band voltage, and dielectric constant of 1,054, -0.45V, and 46, respectively. By catalyzing, tetragonality was increased, and stable films were formed. For films with thickness of 0.12㎛(heat treated at 500℃ for 60min), grain growth were constrained by substrate, and grain size distributions were bimnodal, and perovskite structures were not crystallized. But, for films with thickness of 0.36㎛, the degree of constraint of grain growth and bimodal grain size distributions were reduced, and perovskite structures were easily crystallized. So, it is desirable to apply to microelectronics that the thickness of lead titanate thin films is thicker than 1㎛.

서지기타정보

서지기타정보
청구기호 {DMS 9109
형태사항 iv, 149 p. : 삽도 ; 26 cm
언어 한국어
일반주기 저자명의 영문표기 : Jeon-Kook Lee
지도교수의 한글표기 : 김종희
공동교수의 한글표기 : 정형진
지도교수의 영문표기 : Chong-Hee Kim
공동교수의 영문표기 : Hyung-Jin Jung
학위논문 학위논문(박사) - 한국과학기술원 : 재료공학과,
서지주기 참고문헌 : p.141-145
주제 Dielectrics
Ferroelectric storage cells
졸-겔법 --과학기술용어시소러스
티탄산납 --과학기술용어시소러스
유전체 박막 --과학기술용어시소러스
스핀코팅 --과학기술용어시소러스
Thin films
Sol-gel
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