Method for forming a stress-reduced field-effect semiconductor device
First Claim
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1. A method for producing a field-effect semiconductor device, the method comprising:
- providing a semiconductor body with a first surface defining a vertical direction;
defining an active area;
forming a vertical trench from the first surface into the semiconductor body;
forming a field dielectric layer at least on a side wall and a bottom wall of the vertical trench;
depositing a conductive layer on the field dielectric layer;
forming a closed cavity on the conductive layer in the vertical trench; and
forming an insulated gate electrode on the closed cavity in the vertical trench,wherein an interface between the field dielectric layer and the surrounding semiconductor body is under tensile stress and the closed cavity is filled or unfilled so as to counteract the tensile stress.
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Abstract
A method for producing a field-effect semiconductor device includes providing a semiconductor body with a first surface defining a vertical direction, defining an active area, forming a vertical trench from the first surface into the semiconductor body, forming a field dielectric layer at least on a side wall and a bottom wall of the vertical trench, depositing a conductive layer on the field dielectric layer, forming a closed cavity on the conductive layer in the vertical trench, and forming an insulated gate electrode on the closed cavity in the vertical trench.
11 Citations
16 Claims
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1. A method for producing a field-effect semiconductor device, the method comprising:
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providing a semiconductor body with a first surface defining a vertical direction; defining an active area; forming a vertical trench from the first surface into the semiconductor body; forming a field dielectric layer at least on a side wall and a bottom wall of the vertical trench; depositing a conductive layer on the field dielectric layer; forming a closed cavity on the conductive layer in the vertical trench; and forming an insulated gate electrode on the closed cavity in the vertical trench, wherein an interface between the field dielectric layer and the surrounding semiconductor body is under tensile stress and the closed cavity is filled or unfilled so as to counteract the tensile stress. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for producing a field-effect semiconductor device, comprising:
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providing a semiconductor wafer with a first surface defining a vertical direction; defining an active area of the field-effect semiconductor device; forming in the active area at least one trench gate electrode and a gate dielectric region, the gate dielectric region insulating the trench gate electrode from the semiconductor wafer; forming in the active area dielectric regions extending from the first surface vertically deeper into the semiconductor wafer than the gate dielectric region; and forming a vertical trench extending from the first surface vertically deeper into the semiconductor wafer than the gate dielectric region to form an expansion joint, wherein the at least one trench gate electrode and the gate dielectric region are formed in a first trench that vertically extends from the first surface into the semiconductor wafer, and wherein the dielectric regions and the expansion joint are formed in a second trench that is laterally separated from the first trench and extends from the first surface into the semiconductor wafer. - View Dependent Claims (13, 14, 15)
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16. A method for producing a field-effect semiconductor device, the method comprising:
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providing a semiconductor body with a first surface defining a vertical direction; defining an active area; forming a vertical trench from the first surface into the semiconductor body; forming a field dielectric layer at least on a side wall and a bottom wall of the vertical trench; depositing a conductive layer on the field dielectric layer; forming a closed cavity on the conductive layer in the vertical trench; and forming an insulated gate electrode on the closed cavity in the vertical trench, wherein forming the closed cavity comprises; isotropic back-etching a filler material in the vertical trench selectively with respect to the conductive layer and the field dielectric layer.
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Specification