Abstract
Photocatalytic machining of the organic molecular layer of octadecyl-trichlorosilane (OTS) coated on a Si wafer was investigated in the atmosphere by use of a porous TiO2 micro wire which was prepared by phase separation and selective leaching process. The OTS coated on the Si wafer surface was clearly machined within 1 min under UV irradiation. From the examination of the effect of humidity on the OTS machining rate, the ambient air was found to have sufficient condition for this machining procedure. On the contrary, the OTS in UV non-irradiated area was not machined at all. This indicated “double excitation mechanism”, which the photo induced oxygen radicals on TiO2 were further photo excited by the irradiation of UV light, proceeded. This process is capable of on-demand machining of organic molecular layer in normal atmospheric condition.
