Trenched shield gate power semiconductor devices and methods of manufacture
First Claim
1. A semiconductor device comprising:
- a drift region of a first conductivity type;
a well region extending above the drift region and having a second conductivity type opposite the first conductivity type;
an active trench extending through the well region and into the drift region, the active trench having its sidewalls and bottom lined with dielectric material, and substantially filled with a first conductive layer and a second conductive layer, the second conductive layer forming a gate electrode and being disposed above the first conductive layer and separated therefrom by inter-electrode dielectric material;
source regions having the first conductivity type formed in the well region adjacent the active trench;
a charge control trench extending deeper into the drift region than the active trench and substantially filled with material to allow for vertical charge control in the drift region;
wherein the charge control trench is lined with a layer of dielectric material and substantially filled with conductive material; and
wherein the active trench further comprises a third conductive layer disposed below the first conductive layer, the third conductive layer is smaller than the first conductive layer.
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Accused Products
Abstract
A semiconductor power device includes a drift region of a first conductivity type, a well region extending above the drift region and having a second conductivity type opposite the first conductivity type, an active trench extending through the well region and into the drift region. The active trench, which includes sidewalls and bottom lined with dielectric material, is substantially filled with a first conductive layer and a second conductive layer. The second conductive layer forms a gate electrode and is disposed above the first conductive layer and is separated from the first conductive layer by an inter-electrode dielectric material. The device also includes source regions having the first conductivity type formed inside the well region and adjacent the active trench and a charge control trench that extends deeper into the drift region than the active trench and is substantially filled with material to allow for vertical charge control in the drift region. The charge control trench can be lined with a layer of dielectric material and substantially filled with conductive material. The active trench can include a second shield electrode made of conductive material disposed below the first shield electrode. The first conductive layer inside the active trench can form a secondary gate electrode that is configured to be electrically biased to a desired potential. The semiconductor device can also include a Schottky structure formed between the charge control trench and a second adjacent charge control trench.
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Citations
23 Claims
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1. A semiconductor device comprising:
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a drift region of a first conductivity type; a well region extending above the drift region and having a second conductivity type opposite the first conductivity type; an active trench extending through the well region and into the drift region, the active trench having its sidewalls and bottom lined with dielectric material, and substantially filled with a first conductive layer and a second conductive layer, the second conductive layer forming a gate electrode and being disposed above the first conductive layer and separated therefrom by inter-electrode dielectric material; source regions having the first conductivity type formed in the well region adjacent the active trench; a charge control trench extending deeper into the drift region than the active trench and substantially filled with material to allow for vertical charge control in the drift region; wherein the charge control trench is lined with a layer of dielectric material and substantially filled with conductive material; and wherein the active trench further comprises a third conductive layer disposed below the first conductive layer, the third conductive layer is smaller than the first conductive layer.
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2. A semiconductor device comprising:
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a drift region of a first conductivity type; a well region extending above the drift region and having a second conductivity type opposite the first conductivity type; an active trench extending through the well region and into the drift region, the active trench having its sidewalls and bottom lined with dielectric material, and substantially filled with a first conductive layer and a second conductive layer, the second conductive layer forming a gate electrode and being disposed above the first conductive layer and separated therefrom by inter-electrode dielectric material, the first conductive layer forming a first shield electrode; source regions having the first conductivity type formed in the well region adjacent the active trench; a charge control trench extending deeper into the drift region than the active trench and substantially filled with material to allow for vertical charge control in the drift region; and wherein the active trench further comprises a second shield electrode made of conductive material disposed below the first shield electrode, the second shield electrode is smaller than the first shield electrode. - View Dependent Claims (3, 4)
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5. A semiconductor device comprising:
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a drift region of a first conductivity type; a well region extending above the drift region and having a second conductivity type opposite the first conductivity type; an active trench extending through the well region and into the drift region, the active trench having its sidewalls and bottom lined with dielectric material, and substantially filled with a first conductive layer and a second conductive layer, the second conductive layer forming a gate electrode and being disposed above the first conductive layer and separated therefrom by inter-electrode dielectric material; source regions having the first conductivity type formed in the well region adjacent the active trench; a charge control trench extending deeper into the drift region than the active trench and substantially filled with material to allow for vertical charge control in the drift region; wherein the charge control trench is substantially filled with dielectric material; and wherein the active trench further comprises a third conductive layer disposed below the first conductive layer, the third conductive layer is smaller than the first conductive layer. - View Dependent Claims (6)
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7. A semiconductor device comprising:
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a drift region of a first conductivity type; a well region extending above the drift region and having a second conductivity type opposite the first conductivity type; an active trench extending through the well region and into the drift region, the active trench having its sidewalls and bottom lined with dielectric material, and substantially filled with a first conductive layer and a second conductive layer, the second conductive layer forming a gate electrode and being disposed above the first conductive layer and separated therefrom by inter-electrode dielectric material; source regions having the first conductivity type formed in the well region adjacent the active trench; a charge control trench extending deeper into the drift region than the active trench and substantially filled with material to allow for vertical charge control in the drift region; and a Schottky structure formed between the charge control trench and a second adjacent charge control trench.
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8. A semiconductor device comprising:
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a drift region of a first conductivity type; a well region extending above the drift region and having a second conductivity type opposite the first conductivity type; an active trench extending through the well region and into the drift region, the active trench having its sidewalls and bottom lined with dielectric material, and substantially filled with a first conductive layer and a second conductive layer, the second conductive layer forming a gate electrode and being disposed above the first conductive layer and separated therefrom by inter-electrode dielectric material; source regions having the first conductivity type formed in the well region adjacent the active trench; a charge control trench extending deeper into the drift region than the active trench and substantially filled with material to allow for vertical charge control in the drift region; wherein the first conductive layer inside the active trench forms a secondary gate electrode that is configured to be electrically biased to a desired potential; and wherein the active trench further comprises a third conductive layer disposed below the first conductive layer, the third conductive layer is smaller than the first conductive layer. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 23)
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22. A semiconductor device comprising
a drift region of a first conductivity type; -
a well region extending above the drift region and having a second conductivity type opposite the first conductivity type; an active trench extending through the well region and into the drift region, the active trench having its sidewalls and bottom lined with dielectric material, and substantially filled with a first conductive layer and a second conductive layer, the second conductive layer forming a gate electrode and being disposed above the first conductive layer and separated therefrom by inter-electrode dielectric material; source regions having the first conductivity type formed in the well region adjacent the active trench; a charge control trench extending deeper into the drift region than the active trench and substantially filled with material to allow for vertical charge control in the drift region; and a Schottky structure formed between the charge control trench and a second adjacent charge control trench; wherein the first conductive layer inside the active trench forms a secondary gate electrode that is configured to be electrically biased to a desired potential.
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Specification