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US 11,848,169 B1Granted
Field-emission type electron source and charged particle beam device using the same
OwnerDazhi Chen, Zhongwei Cheninventors
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Abstract
A field-emission type electron source includes (i) a single-crystal tungsten rod having a sharpened terminus and (ii) a mass of ZrO formed only on a portion of the surface, or the entire surface, of the sharpened terminus. In preferred design, the single-crystal tungsten rod is placed in a gaseous medium that consists of oxygen and a non-oxygen gas. The molar ratio between oxygen and the non-oxygen gas is greater than 1:1.
Claims20
A field-emission type electron source comprising:
- (i) a single-crystal tungsten rod having a sharpened terminus extending from a rod body, wherein (1) the rod body immediately adjacent to the terminus has a diameter Db, (2) the terminus has a length Lt along an elongation direction of the tungsten rod;
- and (3) the terminus is so sharpened that its diameter Dt (Dt<Db) is decreased non-linearly along the length Lt from a value that is slightly smaller than Db to a minimal value Dt0 at the apex of the terminus;
- and
- (ii) a mass of ZrO formed on a portion of the surface, or the entire surface, of the sharpened terminus, so as to shorten the distance that the mass of ZrO needs to diffuse to the apex.
1 more element
A field-emission type electron source comprising:
- (i) a single-crystal tungsten rod having a sharpened terminus extending from a rod body, wherein the rod body immediately adjacent to the terminus has a diameter Db, and the terminus is so sharpened that its diameter Dt (Dt<Db) is decreased to a minimal value Dt0 at the apex of the terminus;
- and
- (ii) a mass of ZrO formed only on a portion of the surface, or the entire surface, of the sharpened terminus;
- wherein no ZrO is formed on the single-crystal tungsten rod except the sharpened terminus.
1 more element
A charged particle beam device comprising a field-emission type electron source,
- (A) wherein the field-emission type electron source comprises (i) a single-crystal tungsten rod having a sharpened terminus extending from a rod body, wherein (1) the rod body immediately adjacent to the terminus has a diameter Db, (2) the terminus has a length Lt along an elongation direction of the tungsten rod;
- and (3) the terminus is so sharpened that its diameter Dt (Dt<Db) is decreased non-linearly along the length Lt from a value that is slightly smaller than Db to a minimal value Dt0 at the apex of the terminus;
- and (ii) a mass of ZrO formed on a portion of the surface, or the entire surface, of the sharpened terminus, so as to shorten the distance that the mass of ZrO needs to diffuse to the apex;
- or
- (B) wherein the field-emission type electron source comprises (i) a single-crystal tungsten rod having a sharpened terminus extending from a rod body, wherein the rod body immediately adjacent to the terminus has a diameter Db, and the terminus is so sharpened that its diameter Dt (Dt<Db) is decreased to a minimal value Dt0 at the apex of the terminus;
- and (ii) a mass of ZrO formed only on a portion of the surface, or the entire surface, of the sharpened terminus;
- wherein no ZrO is formed on the single-crystal tungsten rod except the sharpened terminus.
4 more elements
Dependencies are inferred from the claim text.