Laser direct patterning of Si films by Ag-induced layer exchange

Direct patterning of Si films is one of promising methods for TFT display fabrication to achieve low cost. We have proposed laser direct patterning of Si films by Ag-induced layer exchange. In this method, an Ag film was deposited for middle layer between an a-Si film and a substrate. Next, pulsed laser was locally irradiated to the Si/Ag film, and the Ag film was segregated to Si film surface. After that, the Ag film at irradiation area and the Ag film of middle layer at non-irradiation area were etched off by nitric acid treatment. In the result, direct patterning of Si thin films can be achieved at laser irradiation area. Moreover, in order to observe segregation behavior of Ag to Si surface, CW laser was coaxially inserted to surface with the pulsed laser, and reflective intensity of the CW laser was measured by Si-photodetector.