UV Laser Photolysis of Disiloxanes for Chemical Vapor Deposition of Nano-Textured Silicones

Gas-phase photolysis of methyldisiloxanes [(CH 3 ) n H 3 - n Si] 2 O ( n = 1−3) has been achieved for the first time through absorption of ArF laser radiation at 193 nm and has been shown to yield C 1 −C 2 hydrocarbons (major volatile products), methylsilanes (minor volatile products), and solid methylsilicones with their H(Si) content and Si/O ratio reflecting those of the parent compounds. The identified volatile and solid products are compatible with a number of reactions occurring within less than 1 ms in a narrow region of the gaseous sample maintained at room temperature. These reactions are discussed. The solid deposited materials were characterized by FTIR, NMR, UV, and XP spectroscopy, electron microscopy, and thermal gravimetry. They were revealed to contain all possible SiC x H y O z ( x + y + z = 4) compositions, to possess nanometer-sized texture, and to be thermally more stable than linear poly(dialkylsiloxanes).