Power MOSFET device with tungsten spacer in contact hole and method
First Claim
1. A power MOSFET device with a tungsten spacer in its contact hole, the power MOSFET device comprises:
- a substrate;
a body region disposed atop the substrate;
a plurality of trench gates formed in a corresponding plurality of trenches opened through the body region into the substrate;
a plurality of source regions formed on a top portion of the body region around the trench gates;
a dielectric layer formed atop the trench gate and the source regions;
a plurality of contact holes formed through the dielectric layer;
a first barrier layer formed on the side walls and bottom surfaces of the contact holes;
a tungsten spacer disposed atop the first barrier layer at the bottom corners of the contact holes; and
an aluminum contact metal layer disposed over the tungsten spacer and the first barrier layer, filling in the contact holes and extending onto the top surface of the dielectric layer.
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Accused Products
Abstract
The present invention discloses a power MOSFET device with an added tungsten spacer in its contact hole, and manufacturing methods for the device. The features of the device are as follows: It includes trench gate isolated in trench and source/body contacts formed in the contact hole, and the tungsten spacer between Ti/TiN barrier layer and aluminum metal layer, the tungsten spacer is deposited on the bottom corners of the contact hole to cover its bottom corners. The addition of tungsten spacer to the bottom corners of the contact hole can effectively eliminate the presence of pits at the corners and junction spiking due to poor step-coverage of the Ti/TiN barrier layer otherwise leading to direct contact of silicon with aluminum. Thus, the present invention prevents a power MOSFET device from failures due to Idss leakage thus insuring high device quality and yield.
33 Citations
19 Claims
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1. A power MOSFET device with a tungsten spacer in its contact hole, the power MOSFET device comprises:
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a substrate; a body region disposed atop the substrate; a plurality of trench gates formed in a corresponding plurality of trenches opened through the body region into the substrate; a plurality of source regions formed on a top portion of the body region around the trench gates; a dielectric layer formed atop the trench gate and the source regions; a plurality of contact holes formed through the dielectric layer; a first barrier layer formed on the side walls and bottom surfaces of the contact holes; a tungsten spacer disposed atop the first barrier layer at the bottom corners of the contact holes; and an aluminum contact metal layer disposed over the tungsten spacer and the first barrier layer, filling in the contact holes and extending onto the top surface of the dielectric layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method for manufacturing a power MOSFET Device with a tungsten spacer in its contact hole, the method comprises the following steps:
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a) providing a substrate with a body region layer atop; b) opening a plurality of trenches through the body region into the substrate and forming a plurality of trench gates in the plurality of trenches; c) forming source regions on a top portion of the body region and around the trench gate; d) depositing a dielectric layer on top of the trench gate and the source regions; e) opening a plurality of contact holes through the dielectric layer and disposing a first barrier layer on top surface of the dielectric layer, side walls and bottom surfaces of the contact holes; f) disposing a tungsten spacer at the bottom corners of the contact holes while overlaying the first barrier layer; g) disposing an aluminum contact metal layer on the first barrier layer and the tungsten spacer; and h) forming a source contact metal layer and a gate contact metal layer by etching the aluminum contact metal layer and the first barrier layer. - View Dependent Claims (15, 16, 17, 18, 19)
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Specification