III-nitride power 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 power semiconductor device including a first high electron mobility transistor (HEMT) comprising:
a first III-nitride layer;
a second III-nitride layer forming a heterojunction with said first III-nitride layer;
a field nitride layer and a gate nitride on said second III-nitride layer;
a gate metal on said gate nitride;
a plurality of interconnect metal layers including a top metal layer and a bottom metal layer on said second III-nitride layer, said bottom metal layer including a source contact, a drain contact, and a gate contact on said gate metal;
a plurality of vias interconnecting said plurality of interconnect metal layers through a plurality of dielectric layers to connect said source contact, said drain contact, and said gate contact to said top metal layer;
a solderable front metal on said top metal layer, said solderable front metal comprising spaced elongated digits configured for external circuit connection through solder bars.
2. The III-nitride power semiconductor device of claim 1 , wherein said spaced elongated digits alternately expose said source contact and said drain contact.
3. The III-nitride power semiconductor device of claim 1 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.
4. The III-nitride power semiconductor device of claim 1 further comprising a passivation on said top metal layer, said passivation surrounding said solderable front metal.
5. The III-nitride power 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.
6. The III-nitride power semiconductor device of claim 1 , wherein said first III-nitride layer comprises GaN and wherein said second III-nitride layer comprises AlGaN.
7. The III-nitride power semiconductor device of claim 1 , wherein said solderable front metal comprises Titanium-Nickel-Silver (TiNiAg) tri-metal.
8. The III-nitride power semiconductor device of claim 1 , wherein said first III-nitride layer is on a silicon substrate.
9. The III-nitride power semiconductor device of claim 1 , wherein said solderable front metal is soldered with said solder bars to conductive traces of a circuit board for said external circuit connection.
10. The III-nitride power semiconductor device of claim 1 , wherein said solderable front metal is soldered with said solder bars to conductive traces of a circuit board for implementing a DC-DC conversion circuit.
11. A III-nitride power 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 comprising spaced elongated digits exposing a gate contact, a source contact, and a drain contact of said first HEMT, wherein said solderable front metal is configured for external circuit connection through solder bars.
12. The III-nitride power semiconductor device of claim 11 , wherein said spaced elongated digits alternately expose said source contact and said drain contact.
13. The III-nitride power semiconductor device of claim 11 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.
14. The III-nitride power semiconductor device of claim 11 further comprising a passivation on said top metal layer, said passivation surrounding said solderable front metal.
15. The III-nitride power semiconductor device of claim 11 further comprising a passivation on said top metal layer, said passivation selected from the group consisting of epoxy, polyamide, and silicon oxide.
16. The III-nitride power semiconductor device of claim 11 , wherein said first HEMT is an AlGaN/GaN HEMT.
17. The III-nitride power semiconductor device of claim 11 , wherein said solderable front metal comprises Titanium-Nickel-Silver (TiNiAg) tri-metal.
18. The III-nitride power semiconductor device of claim 11 , wherein said first HEMT is disposed on a silicon substrate.
19. The III-nitride power semiconductor device of claim 11 , wherein said solderable front metal is soldered with said solder bars to conductive traces of a circuit board for said external circuit connection.
20. The III-nitride power semiconductor device of claim 11 , wherein said solderable front metal is soldered with said solder bars to conductive traces of a circuit board for implementing a DC-DC conversion circuit.