Hydrolysis and Condensation of n-BuSnCl3: Enabling Deposition of Smooth Metal Oxide Photoresist Thin Films

Herein, we report hydrolysis and condensation chemistries of C4H9SnCl3 to molecular clusters and gel films. Precursor speciation plays a key role in film formation and quality toward realization of atomically smooth surfaces. Density functional theory investigations of C4H9SnCl3 and its reactions show that hydrolysis of the dimer (C4H9Sn)2(OH)2Cl4(H2O)2 has a high energetic penalty in the gas phase and when using a polarizable continuum solvation model based on density. These computations support our observed stability of the dimeric cluster in air, in various solvents, and through initial film deposition. It hydrolyzes and condenses to the [(C4H9Sn)12O14(OH)6]2+ dodecamer on-chip after a post film-deposition bake at 80 °C. Consequently, film surface smoothness is uniquely retained through on-wafer condensation.