Approach to integrate Schottky in MOSFET
First Claim
1. A method for forming an integrated structure combining one or more field effect transistors and a Schottky diode on a lightly-doped semiconductor substrate composition, comprising:
- a) forming a plurality of trenches formed into the substrate composition and extending into the substrate composition forming a plurality of mesas there between,b) substantially filling each trench with a conductive material that is separated from the trench walls by a thin layer of dielectric material to form a gate region of the one or more field effect transistors;
c) forming two doped body regions of a first conductivity type opposite that of the substrate inside each mesa, each doped body region including a corresponding contact trench that extends along a portion of the depth of the substrate composition, whereby there are two contact trenches, the two doped body regions and their corresponding contact trenches being separated by an exposed portion of the substrate composition, wherein each contact trench has an end that abuts the exposed portion of the substrate composition;
d) forming a pair of doped source regions of a second conductivity type inside each doped body region, the pair of doped source regions being positioned adjacent to and on opposite sides of each contact trench; and
e) forming a Schottky diode comprising Schottky barrier metal inside each contact trench of the two doped body regions, the Schottky barrier metal forming a Schottky junction at an interface between the Schottky barrier metal and an exposed vertical sidewall of the exposed portion of the substrate composition separating the two doped body regions.
1 Assignment
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Accused Products
Abstract
An integrated structure combines field effect transistors and a Schottky diode. Trenches formed into a substrate composition extend along a depth of the substrate composition forming mesas therebetween. Each trench is filled with conductive material separated from the trench walls by dielectric material forming a gate region. Two first conductivity type body regions inside each mesa form wells partly into the depth of the substrate composition. An exposed portion of the substrate composition separates the body regions. Second conductivity type source regions inside each body region are adjacent to and on opposite sides of each well. Schottky barrier metal inside each well forms Schottky junctions at interfaces with exposed vertical sidewalls of the exposed portion of the substrate composition separating the body regions.
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Citations
24 Claims
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1. A method for forming an integrated structure combining one or more field effect transistors and a Schottky diode on a lightly-doped semiconductor substrate composition, comprising:
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a) forming a plurality of trenches formed into the substrate composition and extending into the substrate composition forming a plurality of mesas there between, b) substantially filling each trench with a conductive material that is separated from the trench walls by a thin layer of dielectric material to form a gate region of the one or more field effect transistors; c) forming two doped body regions of a first conductivity type opposite that of the substrate inside each mesa, each doped body region including a corresponding contact trench that extends along a portion of the depth of the substrate composition, whereby there are two contact trenches, the two doped body regions and their corresponding contact trenches being separated by an exposed portion of the substrate composition, wherein each contact trench has an end that abuts the exposed portion of the substrate composition; d) forming a pair of doped source regions of a second conductivity type inside each doped body region, the pair of doped source regions being positioned adjacent to and on opposite sides of each contact trench; and e) forming a Schottky diode comprising Schottky barrier metal inside each contact trench of the two doped body regions, the Schottky barrier metal forming a Schottky junction at an interface between the Schottky barrier metal and an exposed vertical sidewall of the exposed portion of the substrate composition separating the two doped body regions. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An integrated structure combining one or more field effect transistors and a Schottky diode on a lightly-doped semiconductor substrate composition, comprising:
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a) a plurality of trenches formed into the substrate composition and extending into the substrate composition forming a plurality of mesas there between, each trench being substantially filled with a conductive material that is separated from the trench walls by a thin layer of dielectric material to form a gate region of the one or more field effect transistors; b) two doped body regions of a first conductivity type opposite that of the substrate composition formed inside each mesa, each doped body region including a corresponding contact trench that extends along a portion of the depth of the substrate composition, whereby there are two contact trenches, the two doped body regions and their corresponding contact trenches being separated by an exposed portion of the substrate composition, wherein each contact trench has an end that abuts the exposed portion of the substrate composition; c) a pair of doped source regions of a second conductivity type formed inside each doped body region, the pair of doped source regions being positioned adjacent to and on opposite sides of each contact trench; and d) a Schottky diode comprising Schottky barrier metal formed inside each contact trench of the two doped body regions, the Schottky barrier metal forming a Schottky junction at an interface between the Schottky barrier metal and an exposed vertical sidewall of the exposed portion of the substrate composition separating the two doped body regions. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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Specification