Top tri-metal system for silicon power semiconductor devices
View Patent ↗A titanium-nickel-palladium solderable metal system for silicon power semiconductor devices ( 10 ), which may be used for one or both of the anode ( 20 ) or cathode ( 30 ). The metal system includes an outer layer of palladium ( 40,70 ), an intermediate layer of nickel ( 50,80 ), and an inner layer of titanium ( 60,90 ). For certain applications, the nickel may be alloyed with vanadium. The metal system may be deposited on bare silicon ( 100 ) or on one or more additional layers of metal ( 110 ) which may include aluminum, aluminum having approximately 1% silicon, or metal silicide. The use of palladium, rather than gold or silver, reduces cost, corrosion, and scratching.
1. A solderable silicon power semiconductor device including an anode deposited on a silicon substrate, and a cathode deposited on the silicon substrate, the device comprising:
the anode including:
an anode outer palladium layer having a thickness approximately between 54×10 −3 μm and 66×10 −3 μm;
an anode intermediate nickel layer having a thickness approximately between 198×10 −3 μm and 242×10 −3 μm, and
an anode inner titanium layer having a thickness approximately between 99×10 −3 μm and 121×10 −3 μm, and
the cathode including:
a cathode outer palladium layer having a thickness approximately between 54×10 −3 μm and 66×10 −3 μm;
a cathode intermediate nickel layer having a thickness approximately between 297×10 −3 μm and 363×10 −3 μm, and
a cathode inner titanium layer having a thickness approximately between 135×10 −3 μm and 165×10 −3 μm.
2. The solderable silicon power semiconductor device as set forth in claim 1 , wherein at least one of the anode intermediate nickel layer and the cathode intermediate nickel layer includes nickel alloyed with approximately 7% vanadium.
3. A solderable silicon power semiconductor device including an anode, a cathode, and a silicon substrate, and one or more additional layers of metal interposed between the silicon substrate and at least one of the anode and the cathode, the device comprising:
the anode including:
an anode outer palladium layer having a thickness approximately between 54×10 −3 μm and 66×10 −3 μm;
an anode intermediate nickel layer having a thickness approximately between 198×10 −3 μm and 242×10 −3 μm; and
an anode inner titanium layer having a thickness approximately between 99×10 −3 μm and 121×10 −3 μm, and
the cathode including:
a cathode outer palladium layer having a thickness approximately between 54×10 −3 μm and 66×10 −3 μm;
a cathode intermediate nickel layer having a thickness approximately between 297×10 −3 μm and 363×10 −3 μm, and
a cathode inner titanium layer having a thickness approximately between 135×10 −3 μm and 165×10 −3 μm.
4. The solderable silicon power semiconductor device as set forth in claim 3 wherein at least one of the anode intermediate nickel layer and the cathode intermediate nickel layer includes nickel alloyed with approximately 7% vanadium.
5. The solderable silicon power semiconductor device as set forth in claim 3 , wherein the one or more additional layers of metal include aluminum.
6. The solderable silicon power semiconductor device as set forth in claim 3 , wherein the one or more additional layers of metal include aluminum having approximately 1% silicon.
7. The solderable silicon power semiconductor device as set forth in claim 3 , wherein the one or more additional layers of metal include metal silicide.
8. The solderable silicon power semiconductor device as set forth in claim 3 , wherein the one or more additional layers of metal include metal silicide and aluminum.
9. The solderable silicon power semiconductor device as set forth in claim 3 , wherein the one or more additional layers of metal include metal silicide and aluminum having approximately 1% silicon.