III-NITRIDE SEMICONDUCTOR DEVICE
A III-nitride power switch that includes a III-nitride heterojunction, field dielectric bodies disposed over the heterojunction, and a gate electrode that does not overlap the top surface of the field dielectric bodies and is disposed over a well in the III-nitride heterojunction.
1 . A III-nitride power semiconductor switch, comprising: a III-nitride heterojunction that includes a III-nitride channel layer and a III-nitride barrier layer formed over said III-nitride channel layer; spaced field dielectric bodies over said III-nitride heterojunction; a well formed in said III-nitride barrier layer; and a gate electrode disposed in the space between said field dielectric bodies and directly over said well in said III-nitride barrier layer, wherein said conductive body does not overlap a top surface of said field dielectric bodies.
2 . The switch of claim 1 , wherein said gate electrode includes a top surface that is coplanar with the top surfaces of said field dielectric bodies.
3 . The switch of claim 1 , further comprising a gate dielectric disposed between said gate electrode and said III-nitride heterojunction.
4 . A III-nitride power semiconductor switch, comprising: a III-nitride heterojunction that includes two III-nitride bodies having different band gaps from one another; field dielectric bodies over said III-nitride heterojunction, said dielectric bodies being spaced from one another by a first space and a second space; a recess formed in a first one of the two III-nitride bodies; a first power electrode disposed in said first space; and a gate electrode disposed in said second space directly over said recess, wherein said gate electrode does not overlap a top surface of said field dielectric bodies.
5 . The switch of claim 4 , further comprising a gate dielectric between said gate electrode and said III-nitride heterojunction.
6 . The switch of claim 4 , wherein said first power electrode does not overlap a top surface of said field dielectric bodies.
7 . The switch of claim 4 , wherein said first power electrode and said gate electrode have top surfaces coplanar with top surfaces of said field dielectric bodies.
8 . The switch of claim 4 , wherein said gate electrode includes a top surface that is coplanar with a top surface of said field dielectric bodies.
9 . A method for fabricating a III-nitride semiconductor switch, comprising: forming a III-nitride heterojunction; forming a recess in said III-nitride heterojunction; forming a field dielectric layer over said III-nitride heterojunction; opening a window inside said field dielectric layer directly over said recess; depositing a conductive body inside said window and over top surfaces of said field dielectric layer; and removing portions of said conductive body from atop said field dielectric layer including any portion of said conductive body that overlaps a top surface of said field dielectric layer.
10 . The method of claim 9 , wherein said portions of said conductive body is removed using CMP.
11 . The method of claim 9 , further comprising covering said top surfaces of said dielectric body and said conductive body inside said window with an etch stop layer; patterning said dielectric body to form another window therein; and depositing another conductive body inside said another window.
12 . The method of claim 9 , further comprising opening another window in said field dielectric layer after said depositing step; and depositing another conductive body in said another window prior to said removing step.
13 . The method of claim 12 , wherein said removing step also removes any portion of said another conductive body that overlaps said field dielectric layer.
14 . The method of claim 13 , wherein said removing comprises a CMP step.