Generation of optical contrast in insulating materials by irradiation with focused ion beams

The optical properties of crystalline insulating materials can markedly be modified by irradiation with energetic ions. The exposed areas of such materials absorb and reflect light more strongly than non-irradiated ones. In this way, optical contrast is created. With modern equipment, ion beams of sufficient intensity can be focused to submicron dimensions. Thus, both analog and digital information can be recorded with pixel densities of Gbit/cm2 to Tbit/cm2. In particular, crystalline films of group-IV elements of the periodic system, such as Si, SiC and CD (diamond), are best suited for this novel ionographic process. The physical foundations of this technology and the resulting properties of the recorded data will be discussed. (orig.)