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AssigneeNational Institute of Advanced Industrial Science and Technology
InventorsTakatoshi Yamada, Shinichi Shikata
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A phosphorus-doped diamond film, which contains phosphorus at a concentration of 1015 cm−3 or more, has a resistivity of 107 Ωcm or less, and allows the voltage for initiation of electron emission to be 30V or less. A method for producing the phosphorus-doped diamond film by growing a diamond film on a diamond substrate by chemical vapor deposition method in an atmosphere containing methane and hydrogen gases and phosphorus with the use of tertiary butyl phosphorus as a source of addition of phosphorus. A diamond electron source having an electrode and a substrate which contains the phosphorous-doped diamond film and emitting electron beams from the phosphorous-doped diamond film when voltage is applied between the electrode and the substrate.
A method for producing a phosphorus-doped diamond film, comprising growing only an n-type diamond film on a diamond substrate by chemical vapor deposition method in an atmosphere containing methane and hydrogen gases and phosphorus with the use of tertiary butyl phosphorus as a source of addition of phosphorous, such diamond film containing phosphorus at a concentration of 1015 cm−3 or more, having a resistivity of 107 Ωcm or less, and allowing the voltage for initiation of electron emission to be 30 V or less.
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Of cold cathodes: of field emission cathodes
Diamond only: using microwave discharges
Diamond only: doping or introduction of a secondary phase in the diamond
Cold cathodes, e.g. field-emissive cathode: field-emissive cathodes
About 1 year 5 months of term left · ends 29 Mar 2028 (estimated)
The present invention relates to a phosphorus-doped diamond film allowing a significantly reduced electron emission voltage, a method for producing the same, and an electron source using the same. A diamond electron source having a carbon-terminated structure can be used as an electron-beam-generating apparatus in fields involving various industrial instruments, household electrical appliances, and the like, such as flat panel displays, discharge tubes, lamps, excitation sources for X-rays or ultraviolet rays, and vacuum micro/nano devices.
With the phosphorus-doped diamond electron source according to the present invention, miniaturization and lower power consumption can be realized. In addition, such diamond electron source is an alternative to existing electron emission sources. Furthermore, development of such diamond electron source in new industrial fields is expected.
Various cold cathodes have been developed through microfabrication technology or thin-film formation technology. Applications of such cold cathodes for electron-beam-generating apparatuses including flat panel displays, discharge tubes, lamps, vacuum micro/nano devices, and the like has been studied. The realization of electronic devices, electronic instruments, and the like using properties of the cold cathodes has been expected. The realization of electronic devices, electronic instruments, and the like is difficult by using solid semiconductor devices. Obtainment of a high current with low voltage is essential for the realization of such application. Accordingly, the applications of cold cathodes have been studied and developed from both material and structural viewpoints.
FIG. 1 is a characteristic graph of the present invention.
FIG. 2 is a characteristic graph of the present invention.
FIG. 3 is a characteristic graph for comparison with a conventional example.
In order to fully utilize the characteristics of phosphorus-doped diamond, it is necessary for such diamond to be formed with a stable surface structure. In view of practical operation environments, an oxygen-terminated structure is preferable. Alternatively, a carbon-terminated structure and a carbon re-constructed surface are also preferable.
The phosphorus-doped diamond used for the present invention is synthesized by a CVD method or obtained by a high-temperature high-pressure method. Diamond obtained by either one of the above methods contains phosphorus added thereto at a concentration of preferably 1016 cm−3 or more and more preferably 1018 cm−3 or more.
A high-concentration phosphorus-doped homoepitaxial diamond thin film synthesized with the use of tertiary butyl phosphorus as a source of addition of phosphorus according to the present invention is mainly characterized in that it contains phosphorus at a concentration of 1016 cm−3 or more (1018 cm−3 or more) and in that the voltage for initiation of electron emission is approximately 20 V to 30 V or less, which is equivalent to 1/30 of such voltage for a high-concentration phosphorus-doped homoepitaxial diamond thin film synthesized with a conventional source of addition of phosphorus when voltage is applied between an electrode and a substrate in an electron source having an electrode and a substrate comprising a diamond film.