Method of making MOSFET by multiple implantations followed by a diffusion step
First Claim
1. A method for manufacturing a metal oxide semiconductor transistor device comprising:
- providing a semiconductor substrate of a first conductivity type;
forming a first insulating layer of silicon dioxide on an active surface of the substrate;
implanting ions of a first conductivity type into said substrate;
depositing a layer of polysilicon on said first insulating layer;
implanting ions of a second conductivity type through said polysilicon layer;
growing a second region of silicon dioxide, said silicon dioxide region being grown over said polysilicon layer;
placing a photoresistive mask over said second oxidation layer for forming a gate of the semiconductor device;
etching a predetermined portion of said second oxidation layer;
plasma etching said polysilicon layer;
removing a predetermined portion of said polysilicon layer underneath said second silicon dioxide layer;
etching said second layer of silicon dioxide;
stripping said photoresist area from said second oxidation layer;
implanting ions of the second conductivity type;
implanting ions of the first conductivity type;
etching said second layer of silicon dioxide overhanging said polysilicon gate layer;
etching said first layer of silicon dioxide surrounding said polysilicon gate layer;
implanting ions of said first conductivity type;
implanting ions of said second conductivity type;
diffusing the implanted ions into said substrate; and
oxidizing the active surface of said substrate, including said polysilicon gate.
1 Assignment
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Accused Products
Abstract
A short channel metal oxide semiconductor transistor device is processed without undesirable short channel effects, such as VT falloff and with a reasonable source-drain operating voltage support. In a substrate lightly doped with P-type conductivity material and source and drain region heavily doped with an N-type conductivity material, two lightly doped N- regions are disposed between the edge of the gate and the source and drain regions. A channel region is more heavily doped with P-type material than the substrate. Two regions extend from opposite sides of the channel region to an area generally below the two N- regions and above the substrate, which regions are more heavily doped than the channel regions.
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Citations
2 Claims
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1. A method for manufacturing a metal oxide semiconductor transistor device comprising:
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providing a semiconductor substrate of a first conductivity type; forming a first insulating layer of silicon dioxide on an active surface of the substrate; implanting ions of a first conductivity type into said substrate; depositing a layer of polysilicon on said first insulating layer; implanting ions of a second conductivity type through said polysilicon layer; growing a second region of silicon dioxide, said silicon dioxide region being grown over said polysilicon layer; placing a photoresistive mask over said second oxidation layer for forming a gate of the semiconductor device; etching a predetermined portion of said second oxidation layer; plasma etching said polysilicon layer; removing a predetermined portion of said polysilicon layer underneath said second silicon dioxide layer; etching said second layer of silicon dioxide; stripping said photoresist area from said second oxidation layer; implanting ions of the second conductivity type; implanting ions of the first conductivity type; etching said second layer of silicon dioxide overhanging said polysilicon gate layer; etching said first layer of silicon dioxide surrounding said polysilicon gate layer; implanting ions of said first conductivity type; implanting ions of said second conductivity type; diffusing the implanted ions into said substrate; and oxidizing the active surface of said substrate, including said polysilicon gate. - View Dependent Claims (2)
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Specification