Method and system for a GaN self-aligned vertical MESFET
View Patent ↗A semiconductor structure includes a III-nitride substrate and a drift region coupled to the III-nitride substrate along a growth direction. The semiconductor substrate also includes a channel region coupled to the drift region. The channel region is defined by a channel sidewall disposed substantially along the growth direction. The semiconductor substrate further includes a gate region disposed laterally with respect to the channel region.
1. A semiconductor structure comprising:
a III-nitride substrate;
a drift region coupled to the III-nitride substrate along a growth direction;
a channel region coupled to the drift region, wherein the channel region is defined by channel sidewalls disposed substantially along the growth direction and a top surface extending laterally between the channel sidewalls;
a gate region comprising a Schottky metal structure and disposed laterally with respect to the channel region; and
a dielectric layer overlying a portion of the top surface of the channel region and the gate region.
2. The semiconductor structure of claim 1 wherein
the Schottky metal structure is not present on the top surface of the channel region.
3. The semiconductor structure of claim 1 wherein:
the drift region comprises a first III-nitride epitaxial layer of a first conductivity type; and
the channel region comprises a second III-nitride epitaxial layer of the first conductivity type coupled to the first III-nitride epitaxial layer.
4. The semiconductor structure of claim 1 wherein the channel sidewall is angled with respect to the growth direction to form a reentrant profile.
5. The semiconductor structure of claim 1 wherein the Schottky metal structure comprises at least one of nickel, platinum, palladium, or gold.
6. The semiconductor structure of claim 1 wherein the drift region has a thickness between 1 μm and 100 μm.
7. The semiconductor structure of claim 1 wherein a width of the channel region measured along a direction orthogonal to the growth direction is less than 5 μm.