SEMICONDUCTOR DEVICE WITH IMPROVED PROTECTION FROM ELECTROSTATIC DISCHARGE
First Claim
1. A semiconductor device having a semiconductor substrate covered by an oxide film, the semiconductor device comprising:
- a drain diffusion formed in the semiconductor substrate, the drain diffusion having a polygonal shape;
a source diffusion formed in the semiconductor substrate, the source diffusion having an annular polygonal shape surrounding the drain diffusion at a certain distance therefrom; and
a plurality of gate electrodes formed on the oxide film, disposed between mutually facing sides of the drain diffusion and the source diffusion, partially overlapping the mutually facing sides of the drain diffusion and the source diffusion, avoiding corners of the drain diffusion.
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Accused Products
Abstract
A concentric polygonal metal-oxide-semiconductor field-effect transistor is designed to avoid overlap between corners of the central drain diffusion and inner corners of the surrounding annular gate electrode. For example, the gate electrode may be reduced to separate straight segments by eliminating the corner portions. Alternatively, the drain diffusion may have a cross shape, and the outer annular source diffusion may be reduced to straight segments facing the ends of the cross, or the source and drain diffusions and gate electrodes may all be reduced to separate straight segments. By avoiding electric field concentration in the corner regions, these designs provide enhanced protection from electrostatic discharge.
34 Citations
18 Claims
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1. A semiconductor device having a semiconductor substrate covered by an oxide film, the semiconductor device comprising:
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a drain diffusion formed in the semiconductor substrate, the drain diffusion having a polygonal shape;
a source diffusion formed in the semiconductor substrate, the source diffusion having an annular polygonal shape surrounding the drain diffusion at a certain distance therefrom; and
a plurality of gate electrodes formed on the oxide film, disposed between mutually facing sides of the drain diffusion and the source diffusion, partially overlapping the mutually facing sides of the drain diffusion and the source diffusion, avoiding corners of the drain diffusion. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A semiconductor device having a semiconductor substrate covered by an oxide film, the semiconductor device comprising:
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a gate electrode formed on the oxide film, having an annular polygonal shape with exterior sides, interior sides, and interior corners;
a plurality of source diffusions formed in the semiconductor substrate, disposed facing and extending beneath respective exterior sides of the gate electrode; and
a drain diffusion formed in the semiconductor substrate, the drain diffusion having a polygonal shape with exterior sides and deleted corners, the exterior sides of the drain diffusion being disposed facing and extending beneath the interior sides of the gate electrode but avoiding the interior corners of the gate electrode. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A semiconductor device having a semiconductor substrate covered by an oxide film, the semiconductor device comprising:
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a plurality of drain diffusions formed in the semiconductor substrate on respective sides of a polygonal area of the semiconductor substrate, avoiding corners of the polygonal area;
a plurality of source diffusions formed in the semiconductor substrate exterior to the polygonal area, facing respective ones of the drain diffusions at a certain distance therefrom; and
a plurality of gate electrodes formed on the oxide film, disposed between mutually facing sides of the plurality of drain diffusions and the plurality of source diffusions, partially overlapping the mutually facing sides of the drain diffusions and the source diffusions. - View Dependent Claims (14, 15, 16, 17, 18)
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Specification