Method and device for improving surface mobility of silicon carbide lateral double-diffusion field effect transistor

The invention discloses a method and device for improving the surface mobility of a silicon carbide lateral double-diffusion field effect transistor. The method comprises the steps: introducing a voltage bias tube, enabling the surface electron concentration of a drift region to be increased when a silicon carbide LDMOS is in forward conduction, enabling the probability that a single electron is captured by a surface trap of an oxide layer above the drift region to be reduced, and enabling the electron mobility to be improved. The device comprises a P-type substrate, which is provided with a P-type isolation layer which divides the device into an LDMOS and a voltage bias tube, the LDMOS comprises a first N-type drift region, a first source region, a first drain region, a gate oxide layer and a polysilicon gate, and is characterized in that four polysilicon field plates which are separated from one another are arranged on the gate oxide layer, the voltage bias tube comprises a second N-type drift region, a sec