Field peak reduction in semiconductor devices with metal corner rounding
View Patent ↗Transistor devices having metal structures with rounded corners are provided. In one example, the transistor device includes a Group III-nitride semiconductor structure. The transistor device includes a gate contact and/or a field plate on the Group III-nitride semiconductor structure. One or more of the gate contact or the field plate includes at least one rounded corner.
1 . A transistor device, comprising:
a Group III-nitride semiconductor structure;
a gate contact on the Group III-nitride semiconductor structure; and
wherein the gate contact comprises at least one rounded corner located at:
an intersection between a top surface of the gate contact and a side surface of the gate contact; or
an intersection between a bottom surface of the gate contact and the side surface of the gate contact.
2 . The transistor device of claim 1 , wherein the at least one rounded corner has a radius of curvature in a range of about 10 nm to about 400 nm.
3 . The transistor device of claim 1 , wherein the at least one rounded corner has a varying radius of curvature transitioning from a first radius of curvature to a second radius of curvature along the at least one rounded corner.
4 . The transistor device of claim 1 , wherein the gate contact comprises an overhang portion of the gate contact, the overhang portion extending toward a source contact or a drain contact of the transistor device, wherein the at least one rounded corner forms a part of the overhang portion.
5 . The transistor device of claim 4 , wherein the gate contact comprises a T-gate or a gamma gate.
6 . The transistor device of claim 1 , wherein the transistor device further comprises a field plate.
7 . The transistor device of claim 6 , wherein the field plate has at least one second rounded corner.
8 . The transistor device of claim 7 , wherein the at least one second rounded corner has a radius of curvature in a range of about 10 nm to about 400 nm.
9 . The transistor device of claim 7 , wherein the at least one second rounded corner has a varying radius of curvature transitioning from a first radius of curvature to a second radius of curvature along the at least one second rounded corner.
10 . The transistor device of claim 7 , wherein the at least one second rounded corner is located at a portion of the field plate at least partially overlapping the gate contact.
11 . The transistor device of claim 7 , wherein the at least one second rounded corner is located at a portion of the field plate extending away from the gate contact.
12 . The transistor device of claim 7 , wherein the at least one second rounded corner is located at a portion of the field plate extending toward the gate contact but not overlapping the gate contact.
13 . The transistor device of claim 1 , wherein the Group III-nitride semiconductor structure comprises a barrier layer, a channel layer, and a two-dimensional electron gas (2DEG) at an interface between the channel layer and the barrier layer.
14 . The transistor device of claim 13 , wherein the channel layer comprises Al w Ga 1-w N, wherein w is 0≤w≤0.1, wherein the barrier layer comprises Al x Ga 1-x N, wherein x is 0.1≤x≤0.4.
15 . The transistor device of claim 1 , wherein the Group III-nitride semiconductor structure is on a substrate, the substrate comprising silicon carbide.
16 . The transistor device of claim 1 , wherein the transistor device comprises a high electron mobility transistor.
17 . A transistor device, comprising:
a Group III-nitride semiconductor structure;
a field plate at least partially overlapping the Group III-nitride semiconductor structure; and
wherein the field plate comprises at least one rounded corner located at an intersection between a lower surface of the field plate and a side surface of the field plate.
18 . A transistor device, comprising:
a substrate;
a Group III-nitride semiconductor structure on the substrate, the Group III-nitride semiconductor structure comprising a barrier layer and a channel layer, the barrier layer having a different bandgap relative to the channel layer;
a gate contact, source contact, and a drain contact, the gate contact having an overhang portion extending toward the drain contact or the source contact;
wherein the gate contact comprises a first rounded corner forming a part of the overhang portion; and
wherein the gate contact comprises a second rounded corner at an intersection between a top surface of the gate contact and a side surface of the gate contact.
19 . The transistor device of claim 18 , wherein the transistor device further comprises a field plate, wherein the field plate has a third rounded corner at a portion of the field plate at least partially overlapping the gate contact, a fourth rounded corner at a portion of the field plate extending away from the gate contact, and a fifth rounded corner at a portion of the field plate extending toward the gate contact but not overlapping the gate contact.