Influence of Si(1 0 0) surface pretreatment on the morphology of TiO2 films grown by atomic layer deposition

Abstract The effect of water plasma treatment of both hydrophobic and hydrophilic Si(1 0 0) surfaces has been studied using infrared spectroscopy to monitor the various surface species present. Exposure to a water plasma results in a significant increase in the concentration of H-bonded hydroxyls and hydrides. Both atomic force microscopy (AFM) and cross-sectional transmission electron microscopy (XTEM) of TiO 2 films deposited by atomic layer deposition at 300 °C, show that the morphology of the films is dependent on the nature of the initial surface. XTEM of the early stages of growth showed that coatings on hydrophilic substrates deposited as initially amorphous and continuous films, which crystallised with further growth. However, the hydrophobic substrate produced island growth of small, crystalline grains. AFM images of 23-nm thick films showed that films deposited on hydrophobic and hydrophilic Si consisted of 35–100 and 150–350 nm crystallites, respectively. A film on water plasma treated Si, closely resembled that on the hydrophilic surface, indicating that hydroxyl groups are responsible for directing the film growth.

[1]  B. Chapman,et al.  Glow Discharge Processes: Sputtering and Plasma Etching , 1980 .

[2]  T. Suntola.  Surface chemistry of materials deposition at atomic layer level , 1996 .

[3]  Y. Chabal,et al.  Ideal hydrogen termination of the Si (111) surface , 1990 .

[4]  M. Schuisky,et al.  Atomic Layer Chemical Vapor Deposition of TiO2 Low Temperature Epitaxy of Rutile and Anatase , 2000 .

[5]  Evgeni P. Gusev,et al.  Structure and stability of ultrathin zirconium oxide layers on Si(001) , 2000 .

[6]  M. Niwano,et al.  Infrared study of chemistry of Si surfaces in etching solution , 1996 .

[7]  S. Fujimura,et al.  Resist stripping in an O2+H2O plasma downstream , 1991 .

[8]  E. Aydil,et al.  In situ probing of surface hydrides on hydrogenated amorphous silicon using attenuated total reflection infrared spectroscopy , 2002 .

[9]  S. Haukka,et al.  An IR and NMR study of the chemisorption of titanium tetrachloride on silica , 1993 .

[10]  D. Hamann,et al.  Physics and chemistry of silicon wafer bonding investigated by infrared absorption spectroscopy , 1996 .

[11]  N. J. Harrick,et al.  Internal reflection spectroscopy , 1968 .

[12]  Yong Bae Kim,et al.  Initial Stage of the Ultrathin Oxide Growth in Water Vapor on Si ( 100 ) Surface , 1999 .

[13]  L. Meda,et al.  Chemistry at silicon crystalline surfaces , 1995 .

[14]  M. L. Hair,et al.  Infrared spectroscopy in surface chemistry , 1967 .

[15]  P. Voort,et al.  Effect of porosity on the distribution and reactivity of hydroxyl groups on the surface of silica gel , 1991 .

[16]  Satoru Watanabe.  Vibrational study on Si(110) surface hydrogenated in solutions , 1996 .

[17]  Pekka Soininen,et al.  Growth of titanium dioxide thin films by atomic layer epitaxy , 1993 .

[18]  M. Ritala,et al.  Atomic force microscopy study of titanium dioxide thin films grown by atomic layer epitaxy , 1993 .

[19]  J. L. Parker,et al.  Plasma modification of mica: forces between fluorocarbon surfaces in water and a nonpolar liquid , 1989 .