Method of fabricating a gallium nitride merged P-I-N schottky (MPS) diode by regrowth and etch back

摘要

An MPS diode includes a III-nitride substrate characterized by a first conductivity type and a first dopant concentration and having a first side and a second side. The MPS diode also includes a III-nitride epitaxial structure comprising a first III-nitride epitaxial layer coupled to the first side of the substrate, wherein a region of the first III-nitride epitaxial layer comprises an array of protrusions. The III-nitride epitaxial structure also includes a plurality of III-nitride regions of a second conductivity type, each partially disposed between adjacent protrusions. Each of the plurality of III-nitride regions of the second conductivity type comprises a first section laterally positioned between adjacent protrusions and a second section extending in a direction normal to the first side of the substrate. The MPS diode further includes a first metallic structure electrically coupled to one or more of the protrusions and to one or more of the second sections.

主权项

1. A method for fabricating an MPS diode, the method comprising:
providing a III-nitride substrate of a first conductivity type having a first surface and a second surface opposing the first surface; forming a first III-nitride epitaxial layer of the first conductivity type coupled to the first surface of the III-nitride substrate, the first III-nitride epitaxial layer having a first surface adjacent the first surface of the III-nitride substrate and a second surface opposing the first surface; forming a mask pattern coupled to the second surface of the first III-nitride epitaxial layer to define etch areas; etching the etch areas to form a plurality of recessed regions extending to a predetermined depth into the first III-nitride epitaxial layer; regrowing a second III-nitride epitaxial layer that fills the recessed regions and extends to a predetermined height from the second surface of the first III-nitride epitaxial layer, wherein the second III-nitride epitaxial layer is lattice matched with the first III-nitride epitaxial layer; forming a second mask pattern coupled to the second III-nitride epitaxial layer to define second etch areas; etching the second etch areas to define a plurality of regrown regions extending in a direction normal to the second surface of the first III-nitride epitaxial layer and to expose a plurality of portions of the first III-nitride epitaxial layer; forming a first metallic structure electrically coupled to one or more of the plurality of regrown regions and one or more of the exposed portions of the first III-nitride epitaxial layer; and forming a second metallic structure electrically coupled to the second surface of the III-nitride substrate.