Chip-scale Schottky device
View Patent ↗A chip-scale schottky package which has at least one cathode electrode and at least one anode electrode disposed on only one major surface of a die, and solder bumps connected to the electrode for surface mounting of the package on a circuit board.
1. A semiconductor device comprising:
a semiconductor die having a first major surface;
a first electrode coupled to a schottky barrier and a portion of said first major surface of said semiconductor die;
a second electrode electrically connected to said first major surface of said semiconductor die, but spaced from said first electrode; wherein respective areas of said first electrode and said second electrode are set to optimize a forward voltage of a schottky diode formed by said schottky barrier; and
a first guard diffusion formed in said semiconductor die in a region surrounding outer perimeter of said second electrode and at least partly directly under but not in direct contact with said first electrode and said first guard diffusion is also at least partly in electrical path between said first electrode and said second electrode, wherein said semiconductor die includes a first lightly doped portion and a second highly doped portion, said first lightly doped portion being disposed over said second highly doped portion, and said semiconductor die further comprising a sinker extending from said second electrode through said first lightly doped portion to said second highly doped portion, and a second guard diffusion surrounding outer perimeter of said first electrode, and wherein said second electrode is electrically connected to said sinker.
2. The device of claim 1 , further comprising a passivation layer disposed over said first electrode and said second electrode, and a plurality of solder bumps disposed over a free surface of said passivation layer and extending through openings in said passivation layer to said first and second electrodes.
3. The device of claim 1 , wherein said first electrode surrounds said second electrode.
4. The device of claim 1 , wherein said first electrode is coupled through said schottky barrier.
5. The device package of claim 4 , wherein said schottky barrier is comprised of molybdenum.
6. The device of claim 4 , wherein said schottky barrier is comprised of palladium.
7. The device of claim 4 , wherein said schottky barrier is comprised of vanadium.
8. The device of claim 1 , wherein said first electrode and said second electrode are comprised of aluminum.
9. The device of claim 2 , further comprising a layer of nickel disposed between at least one of said plurality of solder bumps and an electrode associated with said at least one of said plurality of solder bumps.
10. The device of claim 2 , wherein said passivation layer comprises of silicon nitride.
11. The device of claim 1 , wherein said semiconductor die includes a second major surface opposite to said first major surface, said second major surface being free of any electrical connection.
12. The device of claim 1 , wherein said semiconductor die includes side edges which define lateral boundaries for said semiconductor device.
13. The device of claim 1 , wherein said first electrode is an anode electrode and said second electrode is a cathode electrode.