Investigation of initial stage of sputtered ZnO thin film by TEM.
MEDLÍN, R., NOVÁK, P. Investigation of initial stage of sputtered ZnO thin film by TEM.. Praha, 2014.
|Anglický název:||Investigation of initial stage of sputtered ZnO thin film by TEM.|
|Autoři:||Ing. Rostislav Medlín , Ing. Petr Novák Ph.D.|
|Abstrakt EN:||Zinc Oxide (ZnO) is a wide bandgap semiconductor material which can be successfully used for wide variety of potential applications such as biosensors and acoustic resonator devices. Recently was found that preferred orientation of sputtered ZnO films can be controlled by applied substrate bias and substrate temperature during deposition. This work is focused on the initial growth stage of sputtered ZnO film. Films were deposited by BOC Edwards TF600 sputtering system to formvar coated copper TEM grid glued by carbon paste to silicon substrate. Thin films were deposited at floating potential as well as at bias -100V. Thickness of prepared films varied from 6 nm to 50 nm at both conditions. The films were studied immediately after deposition by HR-TEM JEOL 2200FS equipped with autoemission Schottky gun, in-column energy filter, Oxford EDS detector and Gatan CCD camera with 2048×2048 pixels handled by Digital Micrograph. SAED patterns were treated by Process Diffraction. We found that the biased samples started crystallization process differently and exhibit more random oriented nanocrystals. Lately nanocrystals get predominant orientation of crystallites. Structure of the films prepared at floating have less nanocrystals with 002 reflections oriented parallel with the beam. Moreover, the initial growth stage affects significantly the resulting film structure and preferred orientation. Obtained results will help to understand evolution of sputtered ZnO film structure at different conditions.|