Shielded trench devices
First Claim
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1. A trench device comprising:
- a semiconductor layer of a first conductivity type;
a shield region of a second conductivity type in the semiconductor layer;
a shield polysilicon region of the second conductivity type on the shield region and confined laterally by first dielectric spacers;
a dielectric layer on the shield polysilicon region; and
a trench gate structure on the dielectric layer.
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Abstract
A shield trench power device such as a trench MOSFET or IGBT employs a gate structure with an underlying polysilicon shield region that contacts a shield region in an epitaxial or crystalline layer of the device.
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Citations
35 Claims
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1. A trench device comprising:
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a semiconductor layer of a first conductivity type; a shield region of a second conductivity type in the semiconductor layer; a shield polysilicon region of the second conductivity type on the shield region and confined laterally by first dielectric spacers; a dielectric layer on the shield polysilicon region; and a trench gate structure on the dielectric layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A trench semiconductor device, comprising:
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a substrate making ohmic contact to a bottom electrode; a semiconductor layer of a first conductivity type, the semiconductor layer forming a junction with the substrate; a plurality of shield regions of a second conductivity type in the semiconductor layer; a plurality of shield polysilicon regions of the second conductivity type and confined laterally by dielectric spacers, the shield polysilicon regions respectively being on the shield regions; and a plurality of gate trench structures respectively on the shield polysilicon regions, each of the gate trench structures including; a dielectric layer on an underlying one of the shield polysilicon regions; and a conductive gate on the dielectric layer. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21)
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22. A method of forming a vertical trench power device, the method comprising:
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forming a plurality of gate trenches in a semiconductor layer of a first conductivity type, the semiconductor layer overlying a substrate; forming dielectric spacers on sidewalls of the gate trenches; forming shield regions of a second conductivity type in the semiconductor layer; forming polysilicon shield regions of the second conductivity type in the gate trenches and in contact with the shield regions in the semiconductor layer, the polysilicon shield regions being confined laterally by the dielectric spacers on the sidewalls of the gate trenches; forming dielectric spacers overlying the polysilicon shield regions; and forming conductive gate structures in the gate trenches, the conductive gate structures overlying the dielectric spacers and the polysilicon shield regions. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35)
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Specification