Void isolated III-nitride device
View Patent ↗Isolation of III-nitride devices may be performed with a dopant selective etch that provides a smooth profile with little crystal damage in comparison to previously used isolation techniques. The dopant selective etch may be an electro-chemical or photo-electro-chemical etch. The desired isolation area may be identified by changing the conductivity type of the semiconductor material to be etched. The etch process can remove a conductive layer to isolate a device atop the conductive layer. The etch process can be self stopping, where the process automatically terminates when the selectively doped semiconductor material is removed.
1. An isolation structure for a III-nitride device, comprising:
a base layer having insulative properties and a planar top surface;
a first III-nitride layer overlying the planar top surface of the base layer;
a second III-nitride conductive layer overlying the planar top surface of the base layer and disposed lateral to the first III-nitride layer;
a III-nitride semiconductor device atop the second III-nitride conductive layer; and
an isolation void disposed between the first III-nitride layer and the second III-nitride conductive layer;
a portion of the planar top surface under the first III-nitride layer and the second III-nitride conductive layer comprising a bottom of the isolation void, wherein the void is formed using a dopant selective etch, and wherein the base layer is comprised of a material selected from a group consisting of GaN, Si, SiC, and Sapphire.
2. The structure according to claim 1 , wherein the dopant selective etch is an electro-chemical etch.
3. The structure according to claim 1 , wherein the dopant selective etch is a photo-electro-chemical etch.
4. An isolation structure for a III-nitride device, comprising:
a base layer having a planar top surface;
a first III-nitride layer overlying the planar top surface of the base layer;
a second III-nitride conductive layer overlying the planar top surface of the base layer and disposed lateral to the first III-nitride layer;
a III-nitride semiconductor device on the second III-nitride conductive layer; and
an isolation void disposed between the first III-nitride layer and the second III-nitride conductive layer;
a portion of the planar top surface under the first III-nitride layer and the second III-nitride conductive layer comprising a bottom of the isolation void.
5. The structure according to claim 4 , wherein the void is formed using a dopant selective etch.
6. The structure according to claim 4 , wherein the void is formed using an electro-chemical etch.
7. The structure according to claim 4 , wherein the void is formed using a photo-electro-chemical etch.
8. The structure according to claim 4 , wherein the base layer is comprised of a material selected from a group consisting of GaN, Si, SiC, and Sapphire.
9. The structure according to claim 4 , wherein the second III-nitride conductive layer is on the planar top surface of the base layer.
10. The structure according to claim 4 , wherein the first III-nitride layer is on the planar top surface of the base layer.
11. The structure according to claim 4 , wherein the base layer has insulative properties.
12. The structure according to claim 4 , wherein the second III-nitride conductive layer provides a conduction layer for carrying current in the III-nitride semiconductor device.