Control over Film Thickness of SnO ₂ Ultrathin Film Selectively Deposited on a Patterned Self-Assembled Monolayer

This paper presents a novel process for the fabrication of site-selectively deposited tin oxide ultrathin films (<10 nm) by using molecular recognition between the precursors and the surface of the Si substrate. Using this simple technique, the film thickness of micropatterned tin oxide films was easily controlled. Patterned self-assembled monolayers, in which both hydrophilic and hydrophobic areas formed, were used as templates for the site-selective deposition of the films. Two precursors of SnCl 4 and C 4 H 9 SnCl 3 were selected. The films were selectively deposited on the hydrophilic regions through the liquid phase. The growth rate of the film deposited in SnCl 4 solution was approximately 6 times faster than that in C 4 H 9 SnCl 3 solution. A quartz crystal microbalance measurement implied that film growth could be suppressed by the formation of hydrophobic surfaces on the growing films with increasing immersion time in C 4 H 9 SnCl 3 solution.