AFM Study of Multilayer Sol-gel BaxSr1-xTiO3 Thin Films

Abstract

Multilayer Barium Strontium Titanate (BST) sol-gel films with molar formula Ba_xSr_1-xTiO₃(x= 0.5, 0.7 and 0.8) are deposited on SiO²/Si substrates. The surface morphology and grain size are characterized via Atomic Force Microscope (AFM), showing the films to be uniform and crack-free. The average roughness, maximum peak to valley height, root mean square (RMS) roughness, ten-point mean height roughness, surface skewness and surface kurtosis parameters are used to analyze the surface morphology of the BST thin films. Generally,the results show thatthe surface roughness increases with decreasing Sr content with RMS roughness increasing from 4.77 nm to 6.52nm for films of 160.8 nm thickness as Sr content decreases. Surface roughness also increases with the film thickness, for x= 0.5, RMS roughness increases from 4.77 nm to13.33 nm as the film thickness increases from 160.8 nm to 446.8 nm. A similar trend for
surface roughness is obtained, for all xvalues, as is for grain size.

Keywords:BST; Thin film; Sol-gel; AFM; Surface roughness.

PACS: 68.37.Ps; 68.55.J-; 81.20.Fw; 77.55.fe.