Electron source, method of manufacturing the same, and electron beam apparatus using the same

A method of manufacturing an electron source including a tip of a hexaboride single crystal with <100> orientation, the method comprising:

• electrolytically polishing a front end portion of the tip of the hexaboride single crystal to form the front end portion of the tip in a conical shape;
• and
• heating the tip of the hexaboride single crystal where the front end portion is formed in the conical shape and concurrently applying a voltage having positive polarity with respect to the tip of the hexaboride single crystal such that a top facet of a {100} plane that is surrounded by side facets including at least four {n10} planes and at least four {n10} planes where n represents an integer of 1, 2, or 3 is formed on a side wall of a front end of the front end portion of the tip of the hexaboride single crystal that is formed in the conical shape,
• wherein a total area of the side facets of the {n11} planes is more than a total area of the side facets of the {n10} planes.

An electron beam apparatus comprising:

• an electron source;
• a sample stage on which a sample is mounted;
• and
• an electron optical system that focuses electrons emitted from the electron source into a beam shape and irradiates the sample on the sample stage with the focused beam,
• wherein the electron source includes a tip of a hexaboride single crystal with a <100>axis,
• a top facet of a {100} plane that is surrounded by side facets including at least four {n11} planes and at least four {n10} planes where n represents an integer of 1, 2, or 3 is formed at a front end of the tip of the hexaboride single crystal, and a total area of the side facets of the {n11} planes is more than a total area of the side facets of the {n10} planes.