METHOD OF MANUFACTURING TRENCH FIELD EFFECT TRANSISTORS WITH TRENCHED HEAVY BODY
First Claim
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1. A method of manufacturing a trench field effect transistor on a substrate having a first conductivity type, the method comprising the steps of:
- forming a first trench extending into the substrate;
lining the first trench with dielectric material;
substantially filling the first trench with conductive material to form a gate electrode of the field effect transistor;
forming a body region having a second conductivity type in the substrate;
forming a source region having the first conductivity type inside the body region and adjacent to the first trench;
forming a second trench adjacent to said source region and extending into the body region below the source region; and
filling the second trench with high conductivity material for making contact to the body region.
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Abstract
A process for manufacturing trench field effect transistors improves transistor ruggedness without compromising transistor cell pitch. Instead of a high dose implant and heat cycle, the process of the invention forms the transistor heavy body by etching a trench into the body region and filling the heavy body trench with high conductivity material such as metal that makes contact to both the body and the source region.
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Citations
17 Claims
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1. A method of manufacturing a trench field effect transistor on a substrate having a first conductivity type, the method comprising the steps of:
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forming a first trench extending into the substrate;
lining the first trench with dielectric material;
substantially filling the first trench with conductive material to form a gate electrode of the field effect transistor;
forming a body region having a second conductivity type in the substrate;
forming a source region having the first conductivity type inside the body region and adjacent to the first trench;
forming a second trench adjacent to said source region and extending into the body region below the source region; and
filling the second trench with high conductivity material for making contact to the body region. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A process for manufacturing a trench field effect transistor comprising the steps of:
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etching a first trench in a substrate having a first conductivity type;
lining the first trench with a layer of dielectric material;
substantially filling the trench with polysilicon;
implanting impurities of a second conductivity type into the substrate to form a body region having the second conductivity type over the substrate;
implanting impurities of the first conductivity type inside the body region to form a source region adjacent to the first trench;
etching a second trench through the source region and into the body region; and
filling the second trench with metal making contact with both the source region and the body region. - View Dependent Claims (14, 15, 16, 17)
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Specification