METHOD AND SYSTEM FOR GALLIUM NITRIDE ELECTRONIC DEVICES USING ENGINEERED SUBSTRATES
A method for fabricating an electronic device includes providing an engineered substrate structure comprising a III-nitride seed layer, forming GaN-based functional layers coupled to the III-nitride seed layer, and forming a first electrode structure electrically coupled to at least a portion of the GaN-based functional layers. The method also includes joining a carrier substrate opposing the GaN-based functional layers and removing at least a portion of the engineered substrate structure. The method further includes forming a second electrode structure electrically coupled to at least another portion of the GaN-based functional layers and removing the carrier substrate.
1 . A method for fabricating an electronic device, the method comprising:
providing an engineered substrate structure comprising a III-nitride seed layer;
forming GaN-based functional layers coupled to the III-nitride seed layer;
forming a first electrode structure electrically coupled to at least a portion of the GaN-based functional layers;
joining a carrier substrate opposing the GaN-based functional layers;
removing at least a portion of the engineered substrate structure;
forming a second electrode structure electrically coupled to at least another portion of the GaN-based functional layers; and
removing the carrier substrate.
2 . The method of claim 1 further comprising joining a device substrate to the second electrode prior to removing the carrier substrate.
3 . The method of claim 1 wherein the III-nitride seed layer comprises a GaN material.
4 . The method of claim 1 wherein the III-nitride seed layer comprises an n-type GaN-based material.
5 . The method of claim 1 further comprising epitaxially growing a III-nitride buffer layer coupled to the III-nitride seed layer and a III-nitride drift layer coupled to the III-nitride buffer layer.
6 . The method of claim 5 wherein forming GaN-based functional layers comprises epitaxially growing the GaN-based functional layers.
7 . The method of claim 1 wherein joining the carrier wafer to the GaN-based functional layers comprises:
forming an electrode structure coupled to at least a portion of one of the GaN-based functional layers;
forming a sacrificial bonding layer coupled to another portion of the one of the GaN-based functional layers and at least a portion of the electrode structure; and
bonding the carrier wafer to the sacrificial bonding layer.
8 . The method of claim 7 wherein removing the carrier substrate comprises removing the sacrificial bonding layer.
9 . The method of claim 1 wherein the engineered substrate comprises a handle wafer and a bonding layer coupled to the III-nitride seed layer, and wherein removing at least a portion of the engineered substrate structure comprises mechanically removing the handle wafer, chemically etching the bonding layer, and physically etching the III-nitride seed layer.