Backside ohmic contacts for semiconductor devices
In some aspects, the techniques described herein relate to a semiconductor device including: a substrate having a first side and a second side, the second side being opposite the first side; active circuitry disposed on the first side of the substrate; a metallic implant disposed in the substrate, the metallic implant being a blanket implant on the second side of the substrate; and a metallic layer disposed on the second side of the substrate, the metallic layer and the second side of the substrate including the metallic implant defining an ohmic contact.
1. A semiconductor device comprising:
a substrate having a first side and a second side, the second side being opposite the first side;
active circuitry disposed on the first side of the substrate;
an ohmic contact including:
a metallic implant disposed in the substrate, the metallic implant being a blanket implant on the second side of the substrate; and
a metallic layer disposed on the second side of the substrate.
2. The semiconductor device of claim 1 , wherein the substrate is a silicon substrate.
3. The semiconductor device of claim 1 , wherein the metallic implant includes aluminum.
4. The semiconductor device of claim 3 , wherein the metallic implant further includes at least one of gold, nickel, platinum, palladium, silver, or copper.
5. The semiconductor device of claim 1 , wherein the active circuitry includes a power transistor.
6. The semiconductor device of claim 1 , wherein the metallic layer includes at least one of nickel vanadium, titanium, or silver.
7. The semiconductor device of claim 1 , wherein the metallic implant has an average depth of less than or equal to 10 micrometers.
8. The semiconductor device of claim 7 , wherein the metallic implant includes a plurality of metallic spikes with respective depths greater than the average depth.
9. The semiconductor device of claim 1 , wherein the metallic implant compressively strains the substrate.
10. The semiconductor device of claim 1 , wherein the blanket implant is a first blanket implant, the semiconductor device further comprising an impurity implant disposed in the substrate, the impurity implant being a second blanket implant on the second side of the substrate.
11. A method for producing a semiconductor device comprising:
producing active circuitry on a first side of a semiconductor substrate; and
forming an ohmic contact including:
performing a blanket metallic implant to form an ohmic contact on a second side of the semiconductor substrate, the second side being opposite the first side; and
forming a metallic layer on the second side of the semiconductor substrate.
12. The method of claim 11 , wherein the method further comprises:
prior to performing the blanket metallic implant:
grinding the second side of the semiconductor substrate;
performing a silicon etch on the second side of the semiconductor substrate;
performing an impurity implant on the second side of the semiconductor substrate; and
performing an anneal on the second side of the semiconductor substrate.
13. The method of claim 11 , wherein the method further comprises:
prior to performing the blanket metallic implant, performing an impurity implant on the second side of the semiconductor substrate; and
after performing the blanket metallic implant, performing an anneal on the second side of the semiconductor substrate.
14. The method of claim 11 , wherein the semiconductor substrate is a silicon substrate.
15. The method of claim 11 , wherein performing the blanket metallic implant includes implanting aluminum.
16. The method of claim 15 , wherein performing the blanket metallic implant further includes implanting at least one of gold, nickel, platinum, palladium, silver, or copper.
17. The method of claim 11 , wherein producing the active circuitry includes producing a power transistor.
18. The method of claim 11 , wherein the metallic layer includes at least one of nickel vanadium, titanium, or silver.
19. The method of claim 11 , wherein the blanket metallic implant has an average depth, in the semiconductor substrate, of less than or equal to 10 micrometers.
20. The method of claim 19 , wherein performing the blanket metallic implant includes forming a plurality of metallic spikes with respective depths in the semiconductor substrate greater than the average depth.
21. The method of claim 11 , wherein performing the blanket metallic implant includes at least one of:
heating the semiconductor substrate to a temperature between 250 degrees Celsius and 450 degrees Celsius; or
heating an implanted metallic material to a temperature between 250 degrees Celsius and 450 degrees Celsius.