Power device and fabrication method thereof

A power device comprising at least one vacuum packaged unit structure;

• wherein the unit structure comprises:
• a silicon substrate;
• an emitter formed on the silicon substrate by a silicon-based process;
• a light modulator formed on the silicon substrate by a silicon-based process, the light modulator being configured to generate photons so as to excite the emitter to emit electrons, wherein the light modulator is an ultraviolet LED structure emitting light transversely towards the emitter;
• a collector formed on the silicon substrate by a silicon-based process, the collector being configured to receive the electrons emitted by the emitter, wherein the unit structure is fabricated via:
• fabricating a silicon substrate;
• fabricating a light modulator on the silicon substrate by an epitaxial process, wherein a negative electrode of the light modulator is connected to the silicon substrate, and a positive electrode of the light modulator is led out as a control electrode for light modulation;
• fabricating an emitter on the silicon substrate next to the light modulator;
• and
• combining a pre-fabricated collector with the silicon substrate by a silicon bonding process to form a unit structure;
• and
• a gate formed on the silicon substrate, located between the collector and the emitter for generating an electric field to excite the emitter to emit electrons, wherein the gate improves the file emission modulation efficiency.