Hybrid laser micro/nanofabrication of phase change materials with combination of chemical processing

Phase change materials have been widely applied in optical data storage technique to produce rewritable versions of compact disks and digital versatile disks random access memory and are still promising for higher capacity optical data storage. In optical data storage system, laser irradiation is used to write and read information in phase change film. The original phase state of phase change film without annealing is amorphous state. After laser irradiation, the laser energy transferred to phase change film increases temperature to create crystalline features. To study the effects of laser wavelength and fluence on feature fabrication, different kinds of laser systems are used to irradiate non-annealing phase change film to fabricate crystalline features in micro/nano-sizes. Electrical force microscopy and near-field scanning optical microscopy are used to characterize the electrical and optical properties of phase change film, respectively. Two kinds of phase change film, Ge1Sb2Te4 and Sb2Te3, are used. Alkaline solution has the ability to etch the amorphous and crystalline states of phase change film selectively. The phase change film patterned by laser irradiation is etched by alkaline solution to fabricate two- and three-dimensional structures. The etching selectivity and rate of alkaline solution for the two phase change films are studied. It provides a novel approach to fabricate new functional micro/nano devices by combining further etching or deposition techniques.