Maskless patterning on CVD diamond films by excimer laser

Extensive investigations were conducted in this study to examine the excimer laser ablation process for maskless patterning on chemical vapor deposition (CVD) diamond films. This study has two major topics: (i) macroscopic and microscopic analysis of laser-diamond coupling, and (ii) nature of the laser-induced plasma evolution. These two topics are closely linked to practical fabrication of patterned diamond components by the innovative maskless patterning techniques. The laser-diamond interaction is examined under various gas processing environments. The ablation rate of the CVD diamond film is measured, and linear and nonlinear models for the ablation process are developed. The initial stage of the laser-diamond interaction is observed by the atomic force microscope (AFM) and Raman spectroscope. To examine the development of the surface morphology, in-situ observation is performed by environmental scanning electron microscope (ESEM). Laser-induced plasma on the CVD diamond film is investigated by analytic instrumentations, such as laser-induced breakdown spectroscopy (LIBS), and time-integrated plasma image capturing. The excitation temperatures of the plasma are deduced by the Boltzmann-plot method. Electron densities are calculated from the proportionality between the Stark effect on the line broadening and the electron population. A maskless patterning system has been designed and demonstrated patterning on the diamond films. The results of this investigation establish the great potential of CVD diamond films for various applications, such as semiconductor devices, sensors, optical windows and microelectromechanical systems (MEMS).