The invention provides a
bridge type GaN device and a preparation method thereof. The preparation method comprises the steps of providing a
semiconductor substrate with a buffer structure and an epitaxial structure, forming a
passivation layer on the epitaxial structure, preparing a source
electrode and a drain
electrode, preparing a gate trench, and forming a
bridge type gate structure. Accordingto the invention, the
power density of a
transistor is increased by stacking a plurality of two-dimensional
electron gas channels; through the design of the
bridge type gate structure, based on a gate embedded in the epitaxial structure, the
drain current is controlled by modulating the width of two-dimensional
electron gas through a transverse gate
electric field, so that the roll-off of
transconductance derived from
electron speed modulation is reduced, the
peak value of
transconductance is reduced, the planarization of
transconductance change is realized, and the
linearity of a device is improved; based on the design of a suspended bridge type gate structure, a high
electric field area on the surface is eliminated, the problems of caused current attenuation and collapse are solved, thelack of a contact top gate also eliminates a vertical
electric field at a gate drain end, the inverse piezoelectric effect is greatly inhibited, and the reliability is improved.