Prospects for use of Diamond/Carbon Film for Field Emission Display Applications

摘要

Field emission displays have emerged as a leading contender of low-power flat panel applications. As one of the promising field emission cathodes (FEC), diamond thin film has some unique advantages over its conventional microtip counterpart because of the superior physical and chemical properties of diamond and the simplicity of cathode manufacturing. Over the last year, FEPET, Inc. one of the leading organizations in developing the FEC, has made tremendous progress in its cathode emission performance, film processing, and understanding of emission mechanism. Currently, an emission site density (ESD) of 2x10~5 sites/cm~2 and current density of 100 mA/cm~2 have been achieved at an extraction field of about 10V/mm. We also developed a novel patterning process that allows patterning without applying any post-deposition processing to the film which could degrade its emission properties. The improvement in film emission properties is found to be closely related to a diminishing diamond peak and a strongly accentuated graphitic or amorphous carbon shift in the UV-Raman spectra. High resolution atomic force microscopy (AFM) analysis also showed a possible association of the emission sites with conductive-insulating regions of the surface. Finally, life time studies of sealed carbon film devices will be presented demonstrating a projected life time of over 20,000 hours. With the achievable ESD today, diamond film FEC can already find many practical applications such as low-to-medium resolution displays. Recent results utilizing the HyFED method for high resolution displays will be presented and discussed. Significant improvement in emission site density is still necessary and a glass substrate with high quality surface becomes indispensable. The use of high-temperature glass such as used for polysilicon AMLCDs or a low-temperature diamond thin film deposition process needs, therefore, to be developed.