To provide a thin-film cold cathode improved in the dielectric pressure resistance characteristic of an oxide film between a semiconductor substrate and a thin-film electrode, and its manufacturing method.

This thin-film cold cathode emits electrons into a vacuum by use of hot electrons accelerated within a solid. The thin-film cold cathode includes an Si substrate 1, a tunnel oxide film 2a formed on the Si substrate 1 through thermal oxidation and subjected to a gettering processing, and a thin-film electrode 3 formed on the oxide film 2a. The gettering process is a halogen-containing oxidation process, that is, oxygen O2 with the addition of a halogen-containing gas, e.g. hydrogen chloride HCl, is supplied to effect the thermal oxidation on the Si substrate 1. As a result, the dielectric pressure resistance characteristic of the oxide film 2 can thus be improved.