Vertical ESD protection device
First Claim
1. A method for forming a vertical electrostatic discharge (ESD) protection device, comprising:
- depositing a multi-layer n-type epitaxial layer on a substrate having p-type surface including first epitaxial depositing to form a first n-type epitaxial layer on said p-type surface, and second epitaxial depositing to form a second n-type epitaxial layer formed on said first n-type epitaxial layer, wherein said first n-type epitaxial layer has a peak doping level which is at least double that of said second n-type epitaxial layer, said multi-layer n-type epitaxial layer providing an n-base for a PNP bipolar transistor of said vertical ESD protection device;
forming a p+ layer on said second n-type epitaxial layer;
etching through said p+ layer and said multi-layer n-type epitaxial layer to reach said substrate to form a trench;
filling said trench with a filler material to form a trench isolation region, andforming a metal contact on said p+ layer for providing contact to said p+ layer.
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Abstract
A method for forming a vertical electrostatic discharge (ESD) protection device includes depositing a multi-layer n-type epitaxial layer on a substrate having p-type surface including first epitaxial depositing to form a first n-type epitaxial layer on the p-type surface, and second epitaxial depositing to form a second n-type epitaxial layer formed on the first n-type epitaxial layer. The first type epitaxial layer has a peak doping level which is at least double that of the second n-type epitaxial layer. A p+ layer is formed on the second n-type epitaxial layer. An etch step etches through the p+ layer and multi-layer n-type epitaxial layer to reach the substrate to form a trench. The trench is filled with a filler material to form a trench isolation region. A metal contact is formed on the p+ layer for providing contact to the p+ layer.
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Citations
14 Claims
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1. A method for forming a vertical electrostatic discharge (ESD) protection device, comprising:
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depositing a multi-layer n-type epitaxial layer on a substrate having p-type surface including first epitaxial depositing to form a first n-type epitaxial layer on said p-type surface, and second epitaxial depositing to form a second n-type epitaxial layer formed on said first n-type epitaxial layer, wherein said first n-type epitaxial layer has a peak doping level which is at least double that of said second n-type epitaxial layer, said multi-layer n-type epitaxial layer providing an n-base for a PNP bipolar transistor of said vertical ESD protection device; forming a p+ layer on said second n-type epitaxial layer; etching through said p+ layer and said multi-layer n-type epitaxial layer to reach said substrate to form a trench; filling said trench with a filler material to form a trench isolation region, and forming a metal contact on said p+ layer for providing contact to said p+ layer. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A vertical ESD protection device, comprising:
a substrate having a p-type surface; an multi-layer n-type epitaxial layer including a first n-type epitaxial layer on said p-type surface and a second n-type epitaxial layer on said first n-type epitaxial layer;
wherein said first n-type epitaxial layer has a peak doping level which is at least double that of said second n-type epitaxial layer, said multi-layer n-type epitaxial layer providing an n-base for a PNP bipolar transistor of said vertical ESD protection device;forming a p+ layer on said second n-type epitaxial layer a p+ layer on said second n-type epitaxial layer; a trench isolation region through said p+ layer and said multi-layer n-type epitaxial layer to reach said substrate filled with a filler material, and a metal contact contacting said p+ layer. - View Dependent Claims (9, 10, 11, 12, 13, 14)
Specification