Group III-nitride high-electron mobility transistors with buried p-type layers and process for making the same
An apparatus includes a substrate. The apparatus further includes a group III-nitride buffer layer on the substrate; a group III-nitride barrier layer on the group III-nitride buffer layer, the group III-nitride barrier layer including a higher bandgap than a bandgap of the group III-nitride buffer layer. The apparatus further includes a source electrically coupled to the group III-nitride barrier layer; a gate electrically coupled to the group III-nitride barrier layer; a drain electrically coupled to the group III-nitride barrier layer; and a p-region being at least one of the following: in the substrate or on the substrate below said group III-nitride barrier layer.
1 . An apparatus, comprising:
a substrate;
a group III-Nitride buffer layer on the substrate;
a group III-Nitride barrier layer on the group III-Nitride buffer layer, the group III-Nitride barrier layer comprising a higher bandgap than a bandgap of the group III-Nitride buffer layer;
a source electrically coupled to the group III-Nitride barrier layer;
a gate electrically coupled to the group III-Nitride barrier layer;
a drain electrically coupled to the group III-Nitride barrier layer; and
a p-region being at least one of the following: in the substrate or on the substrate;
wherein the source is electrically connected to the p-region;
wherein the p-region is below the group III-Nitride barrier layer and the p-region is structured and arranged to extend a limited length parallel to the group III-Nitride barrier layer;
wherein the p-region extends to a point before a proximal edge of the gate and the p-region is at most under only part of the gate; and
wherein the proximal edge of the gate is located on the group III-Nitride barrier layer and on a source side of the gate.
2 . The apparatus of claim 1 , further comprising a first connection, wherein the source is electrically connected to the p-region through the first connection.
3 . The apparatus of claim 2 , wherein the first connection extends between a p-type material contact and the source.
4 . The apparatus of claim 2 , wherein the first connection comprises at least one conductive metallic material.
5 . The apparatus of claim 2 , wherein the first connection comprises a metallization.
6 . The apparatus of claim 2 , further comprising a spacer layer, wherein the first connection comprises in part a metallization on the spacer layer.
7 . The apparatus of claim 1 , further comprising a p-type material contact, wherein the p-type material contact is arranged on the p-region.
8 . The apparatus of claim 7 , wherein the p-type material contact is electrically coupled to the p-region and the p-type material contact comprises one or more metal overlayers.
9 . The apparatus of claim 7 , wherein the p-type material contact is formed in or on the group III-Nitride barrier layer.
10 . The apparatus of claim 7 , wherein the p-type material contact is formed in or on the group III-Nitride buffer layer.
11 . The apparatus of claim 7 , further comprising a region or area under or adjacent the p-type material contact comprising implanted p-dopants and/or doped with p-dopants to form an electrical connection with the p-region.
12 . The apparatus of claim 7 , further comprising a recess,
wherein the p-type material contact is arranged in the recess.
13 . The apparatus of claim 7 , wherein the p-type material contact comprises at least one metal overlayer.
14 . The apparatus of claim 12 , wherein the recess is provided in the group III-Nitride buffer layer and the group III-Nitride barrier layer.
15 . The apparatus of claim 12 , wherein the recess extends down to the p-region.
16 . The apparatus of claim 12 , wherein the recess extends down to the group III-Nitride buffer layer.
17 . The apparatus of claim 12 , wherein the p-type material contact is formed in or on the group III-Nitride buffer layer in the recess provided down to the group III-Nitride buffer layer.
18 . The apparatus of claim 12 , wherein the recess is created by removing at least part of the group III-Nitride barrier layer and at least part of the group III-Nitride buffer layer.
19 . The apparatus of claim 2 , further comprising a field plate.
20 . The apparatus of claim 19 , further comprising a second connection connected to the field plate and the source.
21 . The apparatus of claim 20 , wherein the field plate is electrically connected to the source through the second connection.
22 . The apparatus of claim 19 , wherein the first connection and a second connection are configured to connect the field plate to a p-type material contact.
23 . The apparatus of claim 20 , wherein the first connection and the second connection are configured to connect the field plate to a p-type material contact.
24 . The apparatus of claim 1 , wherein the p-region comprises implanted materials.
25 . The apparatus of claim 1 , wherein the p-region is in the substrate below said group III-Nitride barrier layer.
26 . The apparatus of claim 1 , further comprising an epitaxial layer on the substrate and the p-region is in the epitaxial layer.
27 . The apparatus of claim 1 , wherein the p-region is arranged solely in the substrate below said group III-Nitride barrier layer.
28 . The apparatus of claim 1 , further comprising an epitaxial layer on the substrate and the p-region is arranged solely in the epitaxial layer.
29 . The apparatus of claim 1 , further comprising a field plate, wherein the field plate is electrically coupled to said source.
30 . An apparatus, comprising:
a substrate;
a group III-Nitride buffer layer on the substrate;
a group III-Nitride barrier layer on the group III-Nitride buffer layer, the group III-Nitride barrier layer comprising a higher bandgap than a bandgap of the group III-Nitride buffer layer;
a source electrically coupled to the group III-Nitride barrier layer:
a gate electrically coupled to the group III-Nitride barrier layer;
a drain electrically coupled to the group III-Nitride barrier layer; and
a p-region being at least one of the following: in the substrate or on the substrate;
a field plate,
wherein the source is electrically connected to the p-region;
wherein the p-region is below the group III-Nitride barrier layer and the p-region is structured and arranged to extend a limited length parallel to the group III-Nitride barrier layer;
wherein the p-region extends to a point before a proximal edge of the gate;
wherein the proximal edge of the gate is located on the group III-Nitride barrier layer and on a source side of the gate;
wherein the field plate is electrically coupled to said source; and
wherein the p-region is structured and arranged to extend a limited length parallel to the group III-Nitride barrier layer such that the p-region is not located vertically under the gate.
31 . The apparatus of claim 29 , wherein the p-region is structured and arranged to extend an entire length parallel to the group III-Nitride barrier layer.
32 . The apparatus of claim 1 , wherein the p-region extends to a point within about 0 to about 0.3 um of the proximal edge.
33 . The apparatus of claim 1 , wherein the p-region extends to the proximal edge.
34 . The apparatus of claim 1 , wherein the p-region extends 0% to 20% of a gate length past the proximal edge.
35 . The apparatus of claim 1 , wherein the p-region extends 20% to 40% of a gate length past the proximal edge.
36 . The apparatus of claim 1 , wherein the p-region extends 40% to 60% of a gate length past the proximal edge.
37 . The apparatus of claim 1 , wherein the p-region extends 60% to 80% of a gate length past the proximal edge.
38 . A method of making a device comprising:
providing a substrate;
providing a group III-Nitride buffer layer on the substrate;
providing a group III-Nitride barrier layer on the group III-Nitride buffer layer, the group III-Nitride barrier layer comprising a higher bandgap than a bandgap of the group III-Nitride buffer layer;
electrically coupling a source to the group III-Nitride barrier layer;
electrically coupling a gate to the group III-Nitride barrier layer;
electrically coupling a drain to the group III-Nitride barrier layer; and
providing a p-region being at least one of the following: in the substrate or on the substrate,
wherein the source is electrically connected to the p-region;
wherein the p-region is below the group III-Nitride barrier layer and the p-region is structured and arranged to extend a limited length parallel to the group III-Nitride barrier layer;
wherein the p-region extends to a point before a proximal edge of the gate and the p-region is at most under only part of the gate; and
wherein the proximal edge of the gate is located on the group III-Nitride barrier layer and on a source side of the gate.