Schottky rectifier with insulation-filled trenches and method of forming the same

• US 6,710,418 B1
• Filed: 10/11/2002
• Issued: 03/23/2004
• Est. Priority Date: 10/11/2002
• Status: Expired due to Fees

• Current Assignee: Semiconductor Components Industries LLC (ON Semiconductor Corporation)
• Original Assignee: Fairchild Semiconductor Corporation (ON Semiconductor Corporation)
• Inventors: Sapp, Steven P.
• Primary Examiner(s): Flynn, Nathan J.
• Assistant Examiner(s): Forde, Remmon R.
• Application Number:
  US10/269,244
• Time in Patent Office: 529 Days
• Field of Search: 257/471, 257/475, 257/472, 257/476, 257/508, 257/596-600, 257/154, 257/155, 257/168
• US Class Current: 257/471
• 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 29/0657 characterised by the shape of the body
• CPC Class Codes: H01L 29/66143 Schottky diodes
• CPC Class Codes: H01L 29/861 Diodes
• CPC Class Codes: H01L 29/872 Schottky diodes

Abstract

In accordance with an embodiment of the present invention, a semiconductor rectifier includes an insulation-filled trench formed in a semiconductor region. Strips of resistive material extend along the trench sidewalls. The strips of resistive material have a conductivity type opposite that of the semiconductor region. A conductor extends over and in contact with the semiconductor region so that the conductor and the underlying semiconductor region form a Schottky contact.

Claims

1. A semiconductor Schottky rectifier comprising:

a semiconductor region;

insulation-filled trench in the semiconductor region;

strips of resistive material extending along the trench sidewalls, the strips of resistive material having a conductivity type opposite that of the semiconductor region; and

a conductor extending over and in contact with the semiconductor region so that the conductor and the underlying semiconductor region form a Schottky contact through which a substantial portion of a current flows when the Schottky rectifier is forward biased.

2. The semiconductor rectifier of claim 1 further comprising a substrate over which the semiconductor region is formed, the substrate and the semiconductor region having the same conductivity type.

3. The semiconductor rectifier of claim 2 wherein the insulation-filled trench terminates at a junction formed by the semiconductor region and the substrate.

4. The semiconductor rectifier of claim 1 wherein the strips of resistive material are discontinuous along the bottom of the insulation-filled trench.

5. The semiconductor rectifier of claim 1 wherein the strips of resistive material comprise doped silicon material.

6. The semiconductor rectifier of claim 1 wherein the insulation-filled trench terminates within the semiconductor region.

7. The semiconductor rectifier of claim 1 wherein the conductor is in contact with the strips of resistive material.

8. The semiconductor rectifier of claim 1 wherein the conductor is insulated from the strips of resistive material.

9. The semiconductor rectifier of claim 1 wherein the strips of resistive material comprise silicon material having a doping concentration of about four to five times greater than a doping concentration of the semiconductor region.

10. A semiconductor rectifier comprising:

a substrate;

a semiconductor region formed over the substrate, the substrate and the region having the same conductivity type.

at least two insulation-filled trenches laterally spaced in the first semiconductor region to form a mesa region therebetween; and

strips of resistive material extending along the sidewalls of the at least two trenches but being discontinuous along the bottom of the at least two trenches, the strips of resistive material having a conductivity type opposite that of the semiconductor region; and

a conductor extending over and in contact with the semiconductor region so that the conductor and the underlying semiconductor region form a Schottky contact.

11. The semiconductor rectifier of claim 10 wherein the strips of resistive material comprise doped silicon material.

12. The semiconductor rectifier of claim 10 wherein the insulation-filled trench terminates within the semiconductor region.

13. The semiconductor rectifier of claim 10 wherein the conductor is in contact with the strips of resistive material.

14. The semiconductor rectifier of claim 10 wherein the strips of resistive material comprise silicon material having a doping concentration of about four to five times greater than a doping concentration of the semiconductor region.