Power semiconductor device with reduced contact resistance
View Patent ↗A semiconductor device that includes an electrode of one material and a conductive material of lower resistivity formed over the electrode and a process for fabricating the semiconductor device.
1. A semiconductor device comprising:
a semiconductor body including a first surface and a second surface, said semiconductor body comprising a first power electrode on said first surface of said semiconductor body, and a second power electrode on said second surface of said semiconductor body;
a first barrier layer over said first power electrode;
a second barrier layer over said second power electrode;
a first metallic body having a resistivity less than a resistivity of said first power electrode formed over said first barrier layer;
a second metallic body having a resistivity less than a resistivity of said second power electrode formed over said second barrier layer;
wherein said first metallic body is configured for flip-chip mounting over said first surface and said second metallic body is configured for flip-chip mounting over said second surface.
2. The semiconductor device of claim 1 , wherein said first and second power electrodes comprise aluminum.
3. The semiconductor device of claim 1 , wherein said first and second power electrodes comprise AlSi.
4. The semiconductor device of claim 1 , wherein said first and second power electrodes comprise AlSiCu.
5. The semiconductor device of claim 1 , wherein said first and second barrier layers comprise titanium.
6. The semiconductor device of claim 1 , wherein said first and said second metallic bodies comprise copper.
7. The semiconductor device of claim 1 , further comprising a nickel layer over at least one of said first and second metallic bodies.
8. The semiconductor device of claim 1 , further comprising a stress balancing body disposed on at least one of said first and second metallic bodies.
9. The semiconductor device of claim 1 , wherein said semiconductor device is a power MOSFET, and said first and said second power electrodes are, respectively, a source electrode and a drain electrode.
10. The semiconductor device of claim 1 , further comprising a control electrode, a third barrier layer over said control electrode, and a third metallic body having a resistivity less than a resistivity of said control electrode formed over said third barrier layer.
11. The semiconductor device of claim 1 , further comprising a solderable body over said first metallic body.
12. The semiconductor device of claim 11 , wherein said solderable body comprises a nickel layer.
13. The semiconductor device of claim 11 , wherein said solderable body comprises NiAg.
14. The semiconductor device of claim 11 , wherein said solderable body comprises NiAu.
15. The semiconductor device of claim 1 , further comprising a solderable body over said second metallic body.
16. The semiconductor device of claim 15 , wherein said solderable body comprises a nickel layer.
17. The semiconductor device of claim 15 , wherein said solderable body comprises NiAg.
18. The semiconductor device of claim 15 , wherein said solderable body comprises NiAu.
19. The semiconductor device of claim 1 , wherein said first barrier layer prevents contamination of said first power electrode by said first metallic body.
20. The semiconductor device of claim 1 , wherein said second barrier layer prevents contamination of said second power electrode by said second metallic body.