The effect of annealing in laser ablation for epitaxial processing of thin film

• Main Authors: Yueh-Fen Chen, 陳月芬
• Other Authors: Y. S. Gou
• Format: Others
• Language: zh-TW
• Published: 1999
• Online Access: http://ndltd.ncl.edu.tw/handle/84675206506409484858

碩士 === 國立交通大學 === 電子物理系 === 87 === Our goal is investigating homoepitaxy of thin film with as-polished SrTiO3 substrate under the deposition of Laser MBE, and using Reflection High Energy Electron Diffraction to in-situ monitor the evolution of thin film growth. With the characteristic feature of Laser MBE, we can adjust laser repetition rate so that it is possible to manipulate the depositing rate as well. We take this advantage and study the mechanism the thin film growth with various annealing times. It is then observed the dependence of period of RHEED oscillations, the dropping time, and the curve of annealing with different times vs. laser repetition rate, respectively. In the initial stage of growth of thin film, it was found that there are two characteristic temporal scales and one spatial scale to describe the change of RHEED intensity. One characteristic temporal scale is about 10-20 sec. , in which the relaxation time of adatoms is realized. The other is about 50 sec.. It then determines whether the RHEED intensity will follow the foregoing oscillation. The spatial scale indicates that it need the coverage of about 0.4-0.6 monolayer (ML) for the RHEED intensity start oscillation. Under the optimal condition, we can grow SrTiO3 thin film on as-polished SrTiO3 very well, the RHEED intensity kept going the direction of oscillation and did not decay. Based on all these findings, several important empirical formulas related directly to the initial stage of growth mechanism for the epitaxial thin film have been established. We hope that the above observations, to the extent, will assist the future research for epitaxial processing of the oxide thin films.