Schottky diode with improved surge capability

• US 9,412,880 B2
• Filed: 10/12/2010
• Issued: 08/09/2016
• Est. Priority Date: 10/21/2004
• Status: Active Grant

• Current Assignee: Vishay Siliconix
• Original Assignee: Vishay Siliconix
• Inventors: Carta, Rossano, Merlin, Luigi, Bellemo, Laura
• Primary Examiner(s): Dickey, Thomas L
• Application Number:
  US12/903,077
• Publication Number:
  US 20110248284A1
• Time in Patent Office: 2,128 Days
• Field of Search: 257/706, 257/E23.037, 257/E23.051
• US Class Current: 1/1
• CPC Class Codes: H01L 2224/26145 Flow barriers
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 23/49562 for devices being provided for in H01L29/00
• CPC Class Codes: H01L 29/0619 with a supplementary region doped oppositely to or in rectifying contact with the semiconductor containing or contacting region, e.g. guard rings with PN or Schottky junction
• CPC Class Codes: H01L 29/1608 Silicon carbide
• CPC Class Codes: H01L 29/872 Schottky diodes
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/10253 Silicon [Si]
• CPC Class Codes: H01L 2924/12032 Schottky diode
• CPC Class Codes: H01L 2924/13091 Metal-Oxide-Semiconductor Field-Effect Transistor [MOSFET]

Abstract

An SiC Schottky diode die or a Si Schottky diode die is mounted with its epitaxial anode surface connected to the best heat sink surface in the device package. This produces a substantial increase in the surge current capability of the device.

Claims

1. A Schottky diode comprising:

a substrate and a cathode electrode above the substrate, said cathode electrode is a bondable metal;

an epitaxially layer on the bottom of the substrate;

a barrier metal interface located beneath the epitaxially layer;

an anode contact located beneath the barrier metal interface, said anode contact is a solderable metal comprising silver;

a package for said Schottky diode, said package comprising a lead frame located beneath said anode contact, said anode contact is secured to said lead frame; and

a passivation mass is located between the epitaxially layer and said lead frame;

said solderable metal of said anode contact being a spaced distance from said passivation mass such that adjacent sides of said solderable metal and said passivation mass form a gap that extends to the bottom surface of said solderable metal.

2. The Schottky diode of claim 1, further comprising a solder paste located between said anode contact and said lead frame.

3. The Schottky diode of claim 1, wherein said substrate comprises silicon.

4. The Schottky diode of claim 3, wherein said package comprises a cup.

5. The Schottky diode of claim 3, wherein said lead frame comprises metal.

6. The Schottky diode of claim 3, further comprising:

a guard ring in the bottom of said epitaxially layer and surrounding said anode contact,

wherein said passivation mass is disposed between the guard ring and the lead frame.

7. The Schottky diode of claim 6, further comprising a solder paste located between said anode contact and said lead frame.

8. The Schottky diode of claim 1, wherein the substrate comprises silicon carbide.

9. The Schottky diode of claim 8, wherein said lead frame comprises metal.

10. The Schottky diode of claim 8, wherein said package comprises a cup.

11. The Schottky diode of claim 8, further comprising a solder paste located between said anode contact and said lead frame.

12. The Schottky diode of claim 8, further comprising:

a guard ring in the bottom of said epitaxially layer and surrounding said anode contact,

wherein said passivation mass is disposed between the guard ring and the lead frame.

13. The Schottky diode of claim 12, wherein said lead frame comprises metal.

14. The Schottky diode of claim 12, wherein said package comprises a cup.

15. The Schottky diode of claim 12, further comprising a solder paste located between said anode contact and said lead frame.

16. A Schottky diode comprising:

a substrate and a cathode electrode above the substrate, said cathode electrode comprises aluminum;

an epitaxially layer on the bottom of the substrate;

a barrier metal interface located beneath the epitaxially layer;

an anode contact located beneath the barrier metal interface, said anode contact is a solderable metal comprising nickel;

a package for said Schottky diode, said package comprising a lead frame located beneath said anode contact, said anode contact is connected to said lead frame; and

a passivation mass is located between the epitaxially layer and said lead frame;

said solderable metal of said anode contact being a spaced distance from said passivation mass such that adjacent sides of said solderable metal and said passivation mass form a gap that extends to the bottom surface of said solderable metal.

17. The Schottky diode of claim 16, further comprising a solder paste located between said anode contact and said lead frame.

18. The Schottky diode of claim 16, further comprising a guard ring in the bottom of said epitaxially layer and surrounding said anode contact.

19. A Schottky diode comprising:

a substrate and a cathode electrode above the substrate, said cathode electrode comprises aluminum;

an epitaxially layer on the bottom of the substrate;

a barrier metal interface located beneath the epitaxially layer;

an anode contact located beneath the barrier metal interface, said anode contact is a solderable metal comprising chromium;

a package for said Schottky diode, said package comprising a metal lead frame located beneath said anode contact, said anode contact is connected to said metal lead frame; and

a passivation mass is located between the epitaxially layer and said metal lead frame;

said solderable metal of said anode contact being a spaced distance from said passivation mass such that adjacent sides of said solderable metal and said passivation mass form a gap that extends to the bottom surface of said solderable metal.

20. The Schottky diode of claim 19, further comprising:

a guard ring in the bottom of said epitaxially layer and surrounding said anode contact.