Electron beam device including schottky emitter and method of operating schottky emitter

An electron beam device including a Schottky emitter comprising:

• a heating source configured to heat the Schottky emitter;
• a power supply configured to apply an electric field to the Schottky emitter;
• and
• a control unit configured to control the heating source and the power supply, wherein
• the control unit is configured to execute a first stage of applying a first electric field to the Schottky emitter while heating the Schottky emitter at a first temperature, and a second stage of applying a second electric field to the Schottky emitter while heating the Schottky emitter at a second temperature,
• the first temperature is higher than an operation temperature of the Schottky emitter and the second temperature,
• the first electric field is equal to or higher than an operation electric field of the Schottky emitter and lower than the second electric field,
• the second temperature is equal to or higher than the operation temperature and lower than the first temperature, and
• the second electric field is higher than the operation electric field and the first electric field.