Shielded gate trench (SGT) MOSFET cells implemented with a schottky source contact
First Claim
1. A semiconductor power device comprising a plurality of power transistor cells surrounded by a continuously extended trench opened in a semiconductor substrate wherein:
- at least one of said cells constituting an active cell having a source region disposed next to a trenched gate disposed in said extended trench surrounding said cell and electrically connecting to a gate pad wherein said trenched gate further having a bottom shielding electrode filled with a gate material disposed below and insulated from said trenched gate wherein said bottom shielding electrode filled with said gate material having a tapered profile toward a bottom of said trench with a lining layer surrounded said gate material having a correspondingly gradually increased thickness; and
at least an active cell further includes a trenched source contact opened between said trenches wherein said trenched source contact opened through a source region into a body region for electrically connecting the source region to a source metal disposed on top of an insulation layer wherein a trench bottom surface of said trenched source contact further covered with a conductive material to function as an integrated Schottky barrier diode in said active cell.
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Accused Products
Abstract
This invention discloses a semiconductor power device that includes a plurality of power transistor cells surrounded by a trench opened in a semiconductor substrate. At least one active cell further includes a trenched source contact opened between the trenches wherein the trenched source contact opened through a source region into a body region for electrically connecting the source region to a source metal disposed on top of an insulation layer wherein a trench bottom surface of the trenched source contact further covered with a conductive material to function as an integrated Schottky barrier diode in said active cell. A shielding structure is disposed at the bottom and insulated from the trenched gate to provide shielding effect for both the trenched gate and the Schottky diode.
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Citations
39 Claims
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1. A semiconductor power device comprising a plurality of power transistor cells surrounded by a continuously extended trench opened in a semiconductor substrate wherein:
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at least one of said cells constituting an active cell having a source region disposed next to a trenched gate disposed in said extended trench surrounding said cell and electrically connecting to a gate pad wherein said trenched gate further having a bottom shielding electrode filled with a gate material disposed below and insulated from said trenched gate wherein said bottom shielding electrode filled with said gate material having a tapered profile toward a bottom of said trench with a lining layer surrounded said gate material having a correspondingly gradually increased thickness; and at least an active cell further includes a trenched source contact opened between said trenches wherein said trenched source contact opened through a source region into a body region for electrically connecting the source region to a source metal disposed on top of an insulation layer wherein a trench bottom surface of said trenched source contact further covered with a conductive material to function as an integrated Schottky barrier diode in said active cell. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A semiconductor power device comprising a plurality of power transistor cells surrounded by a continuously extended trench opened in a semiconductor substrate wherein:
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at least one of said cells constituting an active cell having a source region disposed next to a trenched gate disposed in said extended trench surrounding said cell and electrically connecting to a gate pad; a gate-to-drain shielding region formed as a body dopant region disposed below said trenched gate; and at least an active cell further includes a trenched source contact disposed substantially at a central portion of said active cell wherein said trenched source contact opened into a source region and extended into a body region of said active cell for electrically connecting the source region to a source metal disposed on top of an insulation layer wherein a trench bottom surface of said trenched source contact further covered with a conductive material to function as an integrated Schottky barrier diode in said active cell. - View Dependent Claims (8, 9, 10, 11)
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12. A semiconductor power device comprising a plurality of power transistor cells surrounded by a continuously extended trench opened in a semiconductor substrate wherein:
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at least one of said cells constituting an active cell having a source region disposed next to a trenched gate disposed in said extended trench surrounding said cell and electrically connecting to a gate pad; a thick oxide layer disposed at the bottom portion below said trenched gate and a body dopant region surrounding a bottom and a lower portions of sidewalls around said thick oxide layer filling the bottom portion in the trench below the trenched gates; and at least an active cell further includes a trenched source contact disposed substantially at a central portion of said active cell wherein said trenched source contact opened into a source region and extended into a body region of said active cell for electrically connecting the source region to a source metal disposed on top of an insulation layer wherein a trench bottom surface of said trenched source contact further covered with a conductive material to function as an integrated Schottky barrier diode in said active cell. - View Dependent Claims (13, 14, 15, 16, 17)
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18. A method for manufacturing a semiconductor power device comprising:
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opening a trench in a substrate for surrounding a plurality of power transistor cells and filling said trench with a gate material; and applying a time etch for etching back said gate material from a selected portion of said trench followed by covering a bottom portion of said gate material in said selected portion of said trench with a shielding insulation to form a bottom shielding electrode while keeping said gate material in a remainder portion of said trench to maintain direct electric connection to said shielding trench bottom; filling said selected portion of said trench with said gate material to form a trenched gate; and forming an insulation layer for covering a top surface of said semiconductor power device and opening a plurality of source contact trenches extending down to a body region between trenched gate and depositing a conductive material over a bottom surface of said source contact trench to function as an integrated Schottky barrier diode in said semiconductor power device. - View Dependent Claims (19)
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20. A semiconductor power device comprising:
a plurality of insulated trenched gate surrounded by a source region doped with a first conductivity type dopant deposited on an upper surface of a body region doped with a second conductivity type dopant opposite to said first conductivity type;
a trenched source contact opened between said trenched gates wherein said trenched source contact opened through said source region into said body region for electrically connecting the source region to a source metal disposed on top of an insulation layer wherein a trench bottom surface of said trenched source contact further covered with a low barrier height metal to function as an integrated Schottky barrier diode in said active cell.- View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29)
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30. A semiconductor power device comprising:
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a plurality of insulated trenched gate surrounded by a source region doped with a first conductivity type dopant deposited on an upper surface of a body region doped with a second conductivity type dopant opposite to said first conductivity type; a trenched source contact opened between said trenched gates wherein said trenched source contact opened through said source region into said body region for electrically connecting the source region to a source metal disposed on top of an insulation layer wherein a trench bottom surface of said trenched source contact further covered with a conductive material to function as an integrated Schottky barrier diode in said active cell; and a shielding structure disposed at the bottom and insulated from said trenched gate. - View Dependent Claims (31, 32, 33, 34, 35, 36, 37, 38, 39)
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Specification