The invention provides a terminal structure of a
semiconductor device, a preparation method thereof and the
semiconductor device. The terminal structure comprises a substrate; the epitaxial layer is positioned on one side of the substrate; the
field oxide layer is at least located on the partial surface, away from the substrate, of the epitaxial layer; the interlayer
dielectric layer is located on the surface, far away from the substrate, of the
field oxide layer, the partial side wall of the
field oxide layer and the partial surface, far away from the substrate, of the epitaxial layer; the at least one first groove is arranged in the interlayer
dielectric layer which is not covered with the field
oxide layer along a first direction, the first groove penetrates into the epitaxial layer, and the first direction is the thickness direction of the substrate; and the
passivation layer is at least located in the first groove and on the surface, away from the substrate, of the interlayer
dielectric layer. The problem that in the prior art, the service life of a planar
silicon carbide MOSFET power
chip is affected due to
water vapor permeation caused by the difference of
thermal expansion coefficients of different dielectric
layers in a high-temperature and high-
humidity environment is solved.