Semiconductor device with cell trench structures and recessed contacts and method of manufacturing a semiconductor device
First Claim
1. A semiconductor device, comprising:
- a plurality of source zones of a first conductivity type formed in a semiconductor substrate as stripes which extend lengthwise in parallel in a first direction;
a plurality of body zones of a second conductivity type opposite the first conductivity type formed in the semiconductor substrate below the plurality of source zones;
a plurality of heavily doped contact zones formed in the body zones;
a plurality of first cell trench structures formed in the semiconductor substrate and extending lengthwise in parallel in a second direction transverse to the first direction so as to transect the stripes of source zones and the body zones, each first cell trench structure comprising a first buried electrode and a first insulator layer between the first buried electrode and the semiconductor substrate;
a plurality of second cell trench structures formed in the semiconductor substrate and extending lengthwise in parallel in the second direction so as to transect the stripes of source zones and the body zones, two or more first cell trench structures of the plurality of first cell trench structures being interposed between neighboring ones of the second cell trench structures, each second cell trench structure comprising a second buried electrode and a second insulator layer between the second buried electrode and the semiconductor substrate;
a recess formed in the first insulator layer along a sidewall of one or more of the first cell trench structures and vertically extending to the corresponding heavily doped contact zone; and
an electrically conductive material disposed in each recess formed in the first insulator layer and contacting the corresponding first buried electrode, the corresponding source zone and the corresponding heavily doped contact zone at the sidewall.
1 Assignment
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Accused Products
Abstract
First and second cell trench structures extend from a first surface into a semiconductor substrate. The first cell trench structure includes a first buried electrode and a first insulator layer between the first buried electrode and a semiconductor mesa separating the first and second cell trench structures. A capping layer covers the first surface. The capping layer is patterned to form an opening having a minimum width larger than a thickness of the first insulator layer. The opening exposes a first vertical section of the first insulator layer at the first surface. An exposed portion of the first insulator layer is removed to form a recess between the semiconductor mesa and the first buried electrode. A contact structure is in the opening and the recess. The contact structure electrically connects both a buried zone in the semiconductor mesa and the first buried electrode and allows for narrower semiconductor mesa width.
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Citations
21 Claims
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1. A semiconductor device, comprising:
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a plurality of source zones of a first conductivity type formed in a semiconductor substrate as stripes which extend lengthwise in parallel in a first direction; a plurality of body zones of a second conductivity type opposite the first conductivity type formed in the semiconductor substrate below the plurality of source zones; a plurality of heavily doped contact zones formed in the body zones; a plurality of first cell trench structures formed in the semiconductor substrate and extending lengthwise in parallel in a second direction transverse to the first direction so as to transect the stripes of source zones and the body zones, each first cell trench structure comprising a first buried electrode and a first insulator layer between the first buried electrode and the semiconductor substrate; a plurality of second cell trench structures formed in the semiconductor substrate and extending lengthwise in parallel in the second direction so as to transect the stripes of source zones and the body zones, two or more first cell trench structures of the plurality of first cell trench structures being interposed between neighboring ones of the second cell trench structures, each second cell trench structure comprising a second buried electrode and a second insulator layer between the second buried electrode and the semiconductor substrate; a recess formed in the first insulator layer along a sidewall of one or more of the first cell trench structures and vertically extending to the corresponding heavily doped contact zone; and an electrically conductive material disposed in each recess formed in the first insulator layer and contacting the corresponding first buried electrode, the corresponding source zone and the corresponding heavily doped contact zone at the sidewall. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method of manufacturing a semiconductor device, the method comprising:
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forming a plurality of source zones of a first conductivity type in a semiconductor substrate as stripes which extend lengthwise in parallel in a first direction; forming a plurality of body zones of a second conductivity type opposite the first conductivity type in the semiconductor substrate below the plurality of source zones; forming a plurality of heavily doped contact zones in the body zones; forming a plurality of first cell trench structures in the semiconductor substrate and extending lengthwise in parallel in a second direction transverse to the first direction so as to transect the stripes of source zones and the body zones, each first cell trench structure comprising a first buried electrode and a first insulator layer between the first buried electrode and the semiconductor substrate; forming a plurality of second cell trench structures in the semiconductor substrate and extending lengthwise in parallel in the second direction so as to transect the stripes of source zones and the body zones, two or more first cell trench structures of the plurality of first cell trench structures being interposed between neighboring ones of the second cell trench structures, each second cell trench structure comprising a second buried electrode and a second insulator layer between the second buried electrode and the semiconductor substrate; forming a recess in the first insulator layer along a sidewall of one or more of the first cell trench structures and vertically extending to the corresponding heavily doped contact zone; and disposing an electrically conductive material in each recess formed in the first insulator layer so as to contact the corresponding first buried electrode, the corresponding source zone and the corresponding heavily doped contact zone at the sidewall. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21)
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Specification