The present invention discloses a n-type
diamond-doped
field effect transistor with a field plate structure. The
field effect transistor comprises
a diamond substrate; a mesa formed by n-type monocrystal
diamond-doped epitaxial film is laid on the
diamond substrate; two strip-shaped
dielectric layers are deposited on the mesa; a drain and a source are respectively laid along the outer edges of each
dielectric layer and the mesa; a gate is laid between the two
dielectric layers; and the dielectric
layers, the drain, the source and the gate constitute a field plate structure. A source extractionelectrode, a drain extraction
electrode and a gate extraction
electrode are respectively deposited on the source, the drain and the gate; and the source extraction
electrode, the drain extraction electrode and the gate extraction electrode are completely separated from each other by a
passivation layer. The invention introduces the field plate structure at the edges of the source, gate and drainelectrodes of the diamond
MESFET, effectively reduces the
electric field concentration effect, increases the breakdown characteristics of the device, effectively reduces the
electric field concentration phenomena at the edges of the source, the gate and the drain of the device and improves the
breakdown voltage of the device.