LOW Qgd TRENCH MOSFET INTEGRATED WITH SCHOTTKY RECTIFIER

• US 20110284954A1
• Filed: 08/02/2011
• Published: 11/24/2011
• Est. Priority Date: 04/15/2009
• Status: Active Grant

• Current Assignee: Force Mos Technology Co., Ltd.
• Original Assignee: Force Mos Technology Co., Ltd.
• Inventors: HSIEH, Fu-Yuan
• Granted Patent: US 8,653,589 B2
• Time in Patent Office: Days
• US Class Current: 257/331
• CPC Class Codes: H01L 21/26586 characterised by the angle between the ion beam and the crystal planes or the main crystal surface
• CPC Class Codes: H01L 29/0878 Impurity concentration or distribution
• CPC Class Codes: H01L 29/1095 Body region, i.e. base region, of DMOS transistors or IGBTs cell layout H01L29/0696
• CPC Class Codes: H01L 29/407 Recessed field plates, e.g. trench field plates, buried field plates
• CPC Class Codes: H01L 29/41766 with at least part of the source or drain electrode having contact below the semiconductor surface, e.g. the source or drain electrode formed at least partially in a groove or with inclusions of conductor inside the semiconductor H01L29/41733 - H01L29/41758 take precedence
• CPC Class Codes: H01L 29/4236 within a trench, e.g. trench gate electrode, groove gate electrode
• CPC Class Codes: H01L 29/456 on silicon
• CPC Class Codes: H01L 29/66727 with a step of recessing the source electrode
• CPC Class Codes: H01L 29/66734 with a step of recessing the gate electrode, e.g. to form a trench gate electrode
• CPC Class Codes: H01L 29/7806 the other device being a Schottky barrier diode
• CPC Class Codes: H01L 29/7813 with trench gate electrode, e.g. UMOS transistors trench gate electrodes per se H01L29/4236
• CPC Class Codes: H01L 29/872 Schottky diodes
• CPC Class Codes: H01L 29/8725 of the trench MOS barrier type [TMBS]

Abstract

An integrated circuit includes a plurality of trench MOSFET and a plurality of trench Schottky rectifier. The integrated circuit further comprises: tilt-angle implanted body dopant regions surrounding a lower portion of all trenched gates sidewalls for reducing Qgd; a source dopant region disposed below trench bottoms of all trenched gates for functioning as a current path for preventing a resistance increased caused by the tilt-angle implanted body dopant regions.

Claims

1. An integrated circuit comprising a trench MOSFET and a trench Schottky rectifier further comprising:

a semiconductor substrate of a first conductivity doping type;

an epitaxial layer of said first conductivity doping type over said semiconductor substrate, wherein said epitaxial layer having a lower doping concentration than said semiconductor substrate;

said trench MOSFET comprising a plurality of first type trenched gates surrounded by source regions of said first conductivity doping type encompassed in body regions of a second conductivity doping type above a drain region disposed on a bottom surface of said semiconductor substrate, and further comprising;

a plurality of tilt-angle implanted body dopant regions surrounding a lower portion of trench sidewalls of said first type trenched gates for reducing Qgd;

a plurality of source dopant regions disposed below trench bottom of said first type trenched gates and adjacent to said tilt-angle implanted body dopant regions for functioning as a current path between said drain region to said source regions for preventing a resistance increase caused by said tilt-angle implanted body dopant regions surrounding said lower portions of said trench sidewalls of said first type trenched gates;

an insulating layer covering said integrated circuit with a source-body contact trench opened in said trench MOSFET through said source regions and extended into said body regions and filled with a contact metal plug overlying a barrier metal layer therein wherein said contact metal plug filled in said source-body contact trench being connected with a source metal;

said trench Schottky rectifier with a plurality of Schottky contact trenches formed into said epitaxial layer and between adjacent second type trenched gates in a different area from said trench MOSFET and having a Schottky silicide barrier layer formed at least along trench sidewalls of said Schottky contact trenches penetrating through said insulating layer and extending into said epitaxial layer filled with said contact metal plug overlying said barrier metal layer directly contacting trench bottoms and said trench sidewalls of said Schottky contact trenches, wherein said source regions and said body regions not exist between said adjacent second type trenched gates in said trench Schottky rectifier, and said contact metal plug filled into said Schottky contact trenches being connected with an anode metal;

said second type trenched gates in said Schottky rectifier surrounded with said tilt-angle implanted body dopant region along trench sidewalls and with said source dopant regions below trench bottoms of said second type trenched gates;

said first type trenched gates in said trench MOSFET and said second type trenched gates in said trench Schottky rectifier comprising a conductive material surrounded with a gate oxide and said second type trenched gates having a greater trench depth than said Schottky contact trenches into said epitaxial layer;

said Schottky rectifier formed at least along said trench sidewalls of said Schottky contact trenches in said epitaxial layer, separated from said conductive material filled in said pair of adjacent second type trenched gates by said epitaxial layer, said tilt-angle implanted body dopant regions and said gate oxide without having said source regions and said body regions surrounding said trench sidewalls of said Schottky contact trenches; and

said source metal and said anode metal being connected together as a source/anode metal.

2. The integrated circuit of claim 1 wherein said first type trenched gates of said trench MOSFET are separated from said second type trenched gates of said trench Schottky rectifier which are shorted with said anode metal of said trench Schottky rectifier.

3. The integrated circuit of claim 1 wherein said first type trenched gates of said trench MOSFET and said second type trenched gates of said trench Schottky rectifier are connected together.

4. The integrated circuit of claim 1 wherein said gate oxide is single gate oxide.

5. The integrated circuit of claim 1 wherein said barrier metal layer lining in said source-body contact trench and said Schottky contact trenches is Ti/TiN or Co/TiN.

6. The integrated circuit of claim 1 wherein said contact metal plugs overlying said barrier metal layers is tungsten.

7. The integrated circuit of claim 1 wherein said Schottky silicide barrier layer comprises TiSi₂ (Ti Silicide) or CoSi₂ (Co Silicide).

8. The integrated circuit of claim 1 wherein said source/anode metal is Ti/Aluminum alloys, Ti/TiN/Aluminum alloys, or Ti/TiN/Copper.

9. The integrated circuit of claim 1 wherein said Schottky silicide barrier layer lines along said trench sidewalls and trench bottoms of said Schottky contact trenches, or only along said trench sidewalk of said Schottky contact trenches.