Localized laser thermal annealing of nanometric SiGe layers protected by a dielectric Bragg mirror

The use of Ge nanostructures in microelectronic devices requires quite low thermal budget processes. In this paper, we report on the development of a technique which enables the localization of laser thermal annealing. Dielectric layers have been deposited on a sample which contains stacks of Ge islands in order to obtain a maximum reflectivity at the wavelength of an XeCl laser (308 nm). We demonstrate that the damage threshold of the dielectric mirror highly depends on the presence of hydrogen in the stack. Last but not least, we demonstrate that localized melting of the surface can be achieved.