Trench Schottky rectifier device and method for manufacturing the same

• US 8,890,279 B2
• Filed: 11/15/2013
• Issued: 11/18/2014
• Est. Priority Date: 10/12/2009
• Status: Active Grant

• Current Assignee: PFC Device Holdings Ltd. (PFC Device, Inc.)
• Original Assignee: PFC Device Corp. (PFC Device, Inc.)
• Inventors: Chao, Kou-Liang, Chen, Mei-Ling, Su, Tse-Chuan, Kuo, Hung-Hsin
• Primary Examiner(s): Toledo, Fernando L
• Assistant Examiner(s): Shamsuzzaman, Mohammed
• Application Number:
  US14/080,904
• Publication Number:
  US 20140077328A1
• Time in Patent Office: 368 Days
• Field of Search: 257/212, 257/263, 257/4, 257/368, 257/330, 257/332, 257/147, 257/484, 438/488, 438/237, 438/582, 438/221, 438/532
• US Class Current: 257/484
• CPC Class Codes: H01L 21/2256 through the applied layer
• CPC Class Codes: H01L 21/28537 Deposition of Schottky electrodes
• CPC Class Codes: H01L 29/0623 Buried supplementary region, e.g. buried guard ring multi-RESURF H01L29/0634
• CPC Class Codes: H01L 29/402 Field plates
• CPC Class Codes: H01L 29/66143 Schottky diodes
• CPC Class Codes: H01L 29/872 Schottky diodes

Abstract

A trench Schottky rectifier device includes a substrate having a first conductivity type, a plurality of trenches formed in the substrate, and an insulating layer formed on sidewalls of the trenches. The trenches are filled with conductive structure. There is an electrode overlying the conductive structure and the substrate, and thus a Schottky contact forms between the electrode and the substrate. A plurality of embedded doped regions having a second conductivity type are formed in the substrate and located under the trenches. Each doped region and the substrate form a PN junction to pinch off current flowing toward the Schottky contact so as to suppress current leakage.

Claims

1. A trench Schottky rectifier device comprising:

a substrate having a first conductivity type;

a first plurality of trenches and a second plurality of trenches formed in the substrate;

an insulating layer formed on sidewalls of the first plurality of trenches and the second plurality of trenches and covered on a first portion of the substrate;

an adhesion layer formed on a second portion of the substrate, the insulating layer, and bottoms of the first plurality of trenches and the second plurality of trenches;

a first plurality of conductive structures formed in the first plurality of trenches and a second plurality of conductive structures formed in the second plurality of trenches;

an electrode overlying the adhesion layer, the first plurality of conductive structures and the second plurality of conductive structures; and

a plurality of doped regions having a second conductivity type formed in the substrate and located under the first plurality of trenches and the second plurality of trenches, and in contact with the adhesion layer at the bottoms of the first plurality of trenches and the second plurality of trenches;

a guard ring having the second conductivity type in an edge area of the substrate.

2. The trench Schottky rectifier device according to claim 1 wherein the electrode is made of aluminum or aluminum alloy, and the adhesion layer is made of titanium or titanium nitride.

3. The trench Schottky rectifier device according to claim 1 wherein the substrate comprises a relatively heavily-doped N-type silicon layer and a relatively lightly-doped N-type epitaxial layer.

4. The trench Schottky rectifier device according to claim 3 wherein the plurality of doped regions comprises P-type dopants.

5. The trench Schottky rectifier device according to claim 1 wherein the conductive structures are metal structures.

6. The trench Schottky rectifier device according to claim 5 wherein the metal structures protrude from the first plurality of trenches and the second plurality of trenches.