III-Nitride device with solderable front metal
View Patent ↗Some exemplary embodiments of a III-nitride power device including a HEMT with multiple interconnect metal layers and a solderable front metal structure using solder bars for external circuit connections have been disclosed. The solderable front metal structure may comprise a tri-metal such as TiNiAg, and may be configured to expose source and drain contacts of the HEMT as alternating elongated digits or bars. Additionally, a single package may integrate multiple such HEMTs wherein the front metal structures expose alternating interdigitated source and drain contacts, which may be advantageous for DC-DC power conversion circuit designs using III-nitride devices. By using solder bars for external circuit connections, lateral conduction is enabled, thereby advantageously reducing device Rdson.
1. A III-nitride semiconductor device comprising:
a first III-nitride layer;
a second III-nitride layer forming a heterojunction with said first III-nitride layer;
a source and a drain over said second III-nitride layer;
a bottom metal layer over said second III-nitride layer, said bottom metal layer including a source contact over said source, and a drain contact over said drain;
a plurality of vias connecting said source contact and said drain contact to a top metal layer situated over said bottom metal layer;
a solderable front metal over said top metal layer.
2. The III-nitride semiconductor device of claim 1 , wherein said solderable front metal comprises spaced elongated digits configured for external circuit connection.
3. The III-nitride semiconductor device of claim 2 , wherein said spaced elongated digits alternately expose said source contact and said drain contact.
4. The III-nitride semiconductor device of claim 1 , wherein said solderable front metal comprises solder bars.
5. The III-nitride semiconductor device of claim 1 , wherein said III-nitride semiconductor device is a high electron mobility transistor (HEMT).
6. The III-nitride semiconductor device of claim 1 , comprising a first transistor and a second transistor, wherein said solderable front metal exposes alternating interdigitated source and drain contacts of said first and second transistors.
7. The III-nitride semiconductor device of claim 1 , further comprising a passivation on said top metal layer, said passivation surrounding said solderable front metal.
8. The III-nitride semiconductor device of claim 1 , further comprising a passivation on said top metal layer, said passivation selected from the group consisting of epoxy, polyamide, and silicon oxide.
9. The III-nitride semiconductor device of claim 1 , wherein said first III-nitride layer comprises GaN and wherein said second III-nitride layer comprises A 1 GaN.
10. The III-nitride semiconductor device of claim 1 , wherein said solderable front metal comprises Titanium-Nickel-Silver (TiNiAg) tri-metal.
11. The III-nitride semiconductor device of claim 1 , wherein said first I 1 I-nitride layer is on a silicon substrate.
12. The III-nitride semiconductor device of claim 1 , wherein said solderable front metal is soldered with solder bars to conductive traces of a circuit board for external circuit connection.
13. The III-nitride semiconductor device of claim 1 , wherein said solderable front metal is soldered with solder bars to conductive traces of a circuit board for implementing a DC-DC conversion circuit.
14. A III-nitride semiconductor device comprising:
a first high electron mobility transistor (HEMT) having multiple interconnect metal layers, said first HEMT including a solderable front metal on a top metal layer, said solderable front metal exposing a source contact and a drain contact of said first HEMT, wherein said solderable front metal is configured for external circuit connection.
15. The III-nitride semiconductor device of claim 14 , further comprising a second HEMT, wherein said solderable front metal of said first HEMT and a solderable front metal of said second HEMT expose alternating interdigitated source and drain contacts.
16. The III-nitride semiconductor device of claim 14 , further comprising a passivation on said top metal layer, said passivation selected from the group consisting of epoxy, polyamide, and silicon oxide.
17. The III-nitride semiconductor device of claim 14 , wherein said first HEMT is an AIGaN/GaN HEMT.
18. The III-nitride semiconductor device of claim 14 , wherein said solderable front metal comprises Titanium-Nickel-Silver (TiNiAg) tri-metal.
19. The III-nitride semiconductor device of claim 14 , wherein said first HEMT is disposed on a silicon substrate.
20. The III-nitride semiconductor device of claim 14 , wherein said solderable front metal is soldered to conductive traces of a circuit board for implementing a DC-DC conversion circuit.