Microplasma generated at solid-solid interface and its application to nanostructure formation

The dynamics of the microplasmas created at a transparent solid-solid interface were investigated extensively. Microplasmas were generated at an interface between a carbon (C) or a germanium (Ge) target and a SiO₂ substrate by irradiating a KrF excimer laser beam onto the target, and the dynamics of the plasmas were investigated with the aid of optical emission spectroscopy. Although the emission spectra that contained the characteristic emission lines and the absorption bands originated from C and Ge species were observed from the C and Ge plasmas without the SiO₂ substrate, identical spectra were obtained from both the plasmas created at the C-SiO ₂ and Ge-SiO₂ interfaces. Furthermore, the target and the Si substrate surfaces were examined with a scanning electron microscope. The SiO₂ substrate was smoothly etched and a nanostructure of a chain-like morphology was also observed in the deposits on the SiO₂ substrate.