Electron beam source and method of manufacturing the same
View Patent ↗A tip of an electron beam source includes a core carrying a coating. The coating is formed from a material having a greater electrical conductivity than a material forming the surface of the core.
1. A source, comprising:
a base;
a tip fixed to the base and extending from the base, the tip comprising:
a core having a surface comprising a first material; and
a coating applied to the core, the coating comprising a second material, the second material forming a surface of the tip;
a first electrical terminal electrically connected to the coating;
an extraction electrode having an opening; and
a second electrical terminal electrically connected to the extraction electrode,
wherein:
the source is an electron beam source; and
at least one of the following conditions is fulfilled:
an electrical conductivity of the first material is less than 10 5 S/m;
an electrical conductivity of the second material is greater than 10 −7 S/m; and
a ratio of the electrical conductivity of the second material to the electrical conductivity of the first material is greater than 10:1.
2. The source according to claim 1 , wherein a surface of an end of the tip that is distal from the base has a radius of curvature that is less than 100 nm.
3. The source according to claim 1 , wherein a dimension of the tip in its longitudinal direction extending away from the base is at least 2 times greater than a maximum dimension of the tip in a direction that is orthogonal to the longitudinal direction of the tip.
4. The source according to claim 1 , wherein a maximum dimension of the tip in its longitudinal direction is at least 50 nm.
5. The source according to claim 1 , wherein a dimension of the tip in its transverse direction is at least 500 nm.
6. The source according to claim 1 , wherein a thickness of the coating of the second material is at least 2 nm.
7. The source according to claim 1 , wherein a thickness of the coating of the second material is less than 50 nm.
8. The source according to claim 1 , wherein a center of the core comprises the first material.
9. The source according to claim 8 , wherein the first material has a modulus of elasticity that is greater than 150 kN/mm 2 .
10. The source according to claim 8 , wherein the first material has a modulus of elasticity that is less than 1100 kN/mm 2 .
11. The source according to claim 1 , wherein the core of the tip includes an inner core comprising a third material different from the first material, and a layer comprising the first material is applied onto the inner core.
12. The source according to claim 11 , wherein the third material has a modulus of elasticity that is greater than 150 kN/mm 2 .
13. The source according to claim 11 , wherein the third material has a modulus of elasticity that is less than 1100 kN/mm 2 .
14. The source according to claim 1 , wherein the first material is diamond-like carbon.
15. The source according to claim 1 , wherein the first material comprises sp 3 -bound carbon.
16. The source according to claim 15 , wherein the first material comprises at least one additive selected from the group consisting of sp 2 -bound carbon, hydrogen, nitrogen, fluorine, and boron.
17. The source according to claim 1 , wherein the first material consists essentially of diamond-like carbon.
18. The source according to claim 1 , wherein the second material comprises a metal.
19. The source according to claim 18 , wherein the metal comprises at least one element selected from the group consisting of Ti, Pt, Al, W, V, Hf, Fe, Co, and Ni.
20. The source according to claim 1 , wherein the second material comprises a semi-conductor material.
21. The source according to claim 20 , wherein the semi-conductor material comprises at least one element selected from the group consisting of Si, Ge, In, Ga and As, P, and Sb.
22. The source according to claim 1 , further comprising a voltage supply configured to supply a voltage to each of the first and second electrical terminals.
23. The source according to claim 1 , wherein a surface of the base includes a convex surface portion extending around an end of the tip close to the base.
24. The source according to claim 23 , wherein a radius of curvature of the convex surface portion of the base is between 10 μm and 0.1 μm.
25. The source according to claim 1 , wherein the base has a surface portion having a surface shape of axial symmetry relative to an axis of symmetry, and an angle between the axis of symmetry and a longitudinal direction of the tip is less than 10°.
26. A system, comprising:
a source according to claim 1 ,
wherein the system is an electron beam system.
27. A method, comprising:
using a source according to claim 1 to perform at least one of the following:
a) generate an electron beam having an electron beam current of at least 0.1 μA;
b) generate an electron microscopic image of an object; and
c) expose a sensitive layer with a predetermined pattern.