| Supported by High-Tech Program Committee of China, Shanghai Institute of Metallurgy, Chinese Academy of Sciences established the first filtered arc deposition (FAD) system in China in 1995. It was successfully used to prepare amorphous diamond (a-D) films as cold cathodic materials for field emission displays (FEDs). We also fabricated a-D cold cathode FED prototype. This work included preparation, doping and characterization of a-D films, study of field emission from a-D films, fabrication of a-D emitter array by oxygen ion beam etching, fabrication and packaging of FEDs.We prepared a series of a-D films at different bias voltages. It showed that they have good properties. The a-D films have more than 85% sp3 bonding. Density of the films is more than 3 glcm3. Band gap of 2.4 eV is obtained. Hardness is about 30 60 GPa. Roughness of less than 1 nm of a 200 nm thick a-D film is achieved.Electron field emission properties of a-D films were studied using a diode structure with phosphor-coated ITO trandparent anode. Field emission is enhanced with increasing sp3 content in a-D films. When sp3 content is about 88 90% in a-D film, its threshold field is less than 2.9 VI~m. Field emission behavior is consistant with Fowler-Nordheim theory. After the surface of a-D film was etched by hydrogen plasma, better field emission properties was obtained. Hydrogen plasma treatment could clean the surface of the a-D film by removing contaminants such as carbonaceous and oxygen- or nitrogen-containing materials and preferentially etches away graphitic on the surface. It could also saturates dangling bonds on the a-D film surface with bydrogen, leading to a hydrogenated lowed-electron-affinity surface. Effect of annealing on electron field emission properties of the a-D films was also studied. It showed that field emission properties were degraded with increasing annealing temperatures. But after the a-D film was annealed at 8000C for 30 mm, enhanced field emission properties was achieved. Its more dense surface protrusions had enhanced field. Field emission from nitrogen-containing a-D films was also studied. The optimal value of nitrogen content in a-D films was about 8~20%.It was also indicated that interface between Si and a-D films could remarkably affect the field emission behavior. As a typical non-carbide-forming metal, Au is rather inert. A rectiFying contact was formed in the interface which degraded field emission properties of a-D films. As typical carbide-forming metal, Ti can interact chemically with carbon at the interface and yield ohmic contacts, which improved field emission properties of a-D films. After a-D/TiISi was annealed at 4300C for 30 mm, further enhanced field emission properties were obtained. At an electric field of 14.3 V/p.m. its emission current density is 2.08 mA/cm2. Field emission site density of 2 x ~ /cm2 is achieved. Because Ti has fine conductivity, Ti can act as electrode and contact with aD films directly and can be applied in FEDs.Patterned a-D film column emitter array was fabricated by oxygen reactive ion beam etching (R1BE). In this process, lithography was requires. Field emission from aD column emitter array was studied. At an electric field of 39 V/p.m. an emission current density of as large as 64.1 mA/cm2 was achieved. Emission site density wasmore than 2 × 10~3/cm~2Field emission from a patterned a-D hole array using a Ti interfacial layer wasalso studied. Threshold field as low as 2.1 V/μm and field emission site up to 3.0 3.5 x 1 ~3 /cm2 were obtained. It is the highest value for diamond-like carbon films ever reported up to now.
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