Many aspects of the present carbon nanotube field emission device and method for manufacturing the same can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present invention. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
Reference will now be made to the drawing figures to describe the preferred embodiments of the present carbon nanotube field emission device and method for manufacturing the same in detail.
Referring to
The at least one spacer 4 is arranged between the cathode 3 and the gate electrode 6 and is configured for separating the cathode 3 and the gate electrode 6. A material of the spacer 4 is selected from the group consisting of SiO2, MgO, Al2O3, ZnO, and a mixture thereof. The at least one spacer 4 defines at least one cavity 9 and the cavity 9 is configured for exposing the cathode 3.
A number of carbon nanotubes 7 as an electron emitter are formed in the at least one cavity 9 and electrically connected with the cathode 3.
The electrically insulating layer 5 is formed on the spacer 4 and defines at least one opening 10. A material of the electrically insulating layer 5 is Si3N4. A thickness of the electrically insulating layer 5 is in the approximate range from 0.1 microns to 1 micron.
The anode 8 faces the electrically insulating layer 5. The least one gate electrode 6 is arranged on the electrically insulating layer 5. That is it that the electrically insulating layer 5 is between the gate electrode 6 and the spacer 4, and the electrically insulating layer 5 covers an underside surface of the gate electrode 6 facing the spacer 4. The gate electrode 6 defines at least one gate electrode hole 11 corresponding to the opening 10. Electrons emitted by the carbon nanotubes 7 shoot onto the anode 8 through the opening 10 and the hole 11.
The electrically insulating layer 5 arranged between the spacer 4 and the gate electrode 6 can prevent the carbon nanotubes 7 touching the gate electrode 6. As a result, short-circuiting between the carbon nanotubes 7 and the gate electrode 6 is significantly reduced and a drain current is reduced.
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At least one gate electrode hole 40 and at least one gate electrode 361 are defined in the gate electrode layer 36. At least one opening 42 and electrically insulating layer 351 are defined in the second electrically insulating layer 35. At least one cavity 39 and at least one spacer 341 are defined in the first electrically insulating layer 34. The second electrically insulating layer 35 is etched through the hole 40 in the gate electrode layer 36 and the first electrically insulating layer 34 is etched through the opening 42 in the second electrically insulating layer 35. Thus, the cathode 33 is exposed. A wet etching method is performed on the first electrically insulating layer 34 and a dry etching method is performed on the gate electrode layer 36 and the second electrically insulating layer 35. The wet etching method uses a solution containing hydrofluoric acid and ammonium fluoride as an etchant. The material of the second electrically insulating layer 35 is different with the material of the first electrically insulating layer 34, therefore, the first electrically insulating layer 34 is thus more etched than the second electrically insulating layer 35. Therefore, the electrically insulating layer 351 can prevent the undersurface of the gate electrode 361 being exposed to the cavity 39.
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Although the present invention has been described with reference to specific embodiments, it should be noted that the described embodiments are not necessarily exclusive, and that various changes and modifications may be made to the described embodiments without departing from the scope of the invention as defined by the appended claims.
Number | Date | Country | Kind |
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200610061307.8 | Jun 2006 | CN | national |