THERMOMECHANICAL WRITING WITH AN ATOMIC FORCE MICROSCOPE TIP

We have developed a new technique to perform fast, reliable nanoindentation of polymer surfaces for possible applications to high density data storage. In this technique, an infrared laser is focused on an atomic force microscope (AFM) tip, which is in contact with a transparent polymethyl methacrylate (PMMA) substrate. The heat from the tip softens the PMMA in the contact region, at which point the local tip pressure creates a pit. The pits range in size from several hundred angstroms to 1-mu-m, depending on the size of the laser pulse and the loading force on the tip. Pits have been made with pulses as short as 0.3-mu-s at loads of 10(-7) N. By operating the AFM on a rotating disk, we have shown that the features can be written and read at frequencies up to at least 100 kHz.