Semiconductor device with elements surrounded by trenches
AssigneeDenso Corporation
InventorsHitoshi Yamaguchi, Yoshitaka Noda
Life of this patent
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Abstract
Pch-MOS transistors to which a power supply potential is applied are respectively surrounded by first trenches, and Nch-MOS transistors to which a ground potential is applied are respectively surrounded by second trenches. The first trenches are surrounded by a third trench, and the second trenches are surrounded by a fourth trench. A silicon layer existing inside the third trench is set at the power source potential. The silicon layer existing between the third and fourth trenches are set at a floating state. Accordingly, each thickness of oxide layers filling the trenches can be reduced.
Claims19
A semiconductor device comprising:
- a first silicon layer;
- a first insulation film disposed on the first silicon layer;
- a second silicon layer disposed on the first insulation film;
- a plurality of first semiconductor elements provided in the second silicon layer to have a first electric potential;
- a plurality of second semiconductor elements provided in the second silicon layer to have a second electric potential smaller than the first electric potential;
- a plurality of first trenches provided in the second silicon layer to reach the first insulation film and respectively surrounding the plurality of first semiconductor elements;
- a plurality of second trenches provided in the second silicon layer to reach the first insulation film and respectively surrounding the plurality of second semiconductor elements;
- a third trench provided in the second silicon layer to reach the first insulation film and surrounding the plurality of first trenches;
- and
- a fourth trench provided in the second silicon layer to reach the first insulation film and surrounding the plurality of second trenches,
- wherein a portion of the second silicon layer between the plurality of first trenches and the third trench has a third electric potential larger than the second electric potential.
A semiconductor device comprising:
- a first silicon layer;
- a first insulation film disposed on the first silicon layer;
- a second silicon layer disposed on the first insulation film;
- a plurality of first semiconductor elements provided in the second silicon layer to have a first electric potential larger than a specific electric potential;
- a plurality of second semiconductor elements provided in the second silicon layer to have a second electric potential smaller than the specific electric potential;
- a first trench provided in the second silicon layer to reach the first insulation film and surrounding all of the plurality of first semiconductor elements;
- and
- a second trench provided in the second silicon layer to reach the first insulation film and surrounding all of the plurality of second semiconductor elements, wherein:
- a first portion of the second silicon layer extending inside the first trench has a third electric potential larger than the specific electric potential;
- a second portion of the second silicon layer extending inside the second trench has a fourth electric potential smaller than the specific electric potential;
- and
- a third portion of the second silicon layer extending outside the first trench and the second trench is electrically floating.
Dependencies are inferred from the claim text.