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US 9,806,172 B2Granted
Vertical tunneling field-effect transistor cell and fabricating the same
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsHarry-Hak-Lay Chuang, Cheng-Cheng Kuo, Ming Zhu
Life of this patent
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Abstract
A tunneling field-effect transistor (TFET) device is disclosed. A protrusion structure is disposed over the substrate and protrudes out of the plane of substrate. Isolation features are formed on the substrate. A drain region is disposed over the substrate adjacent to the protrusion structure and extends to a bottom portion of the protrusion structure as a raised drain region. A drain contact is disposed over the drain region and overlap with the isolation feature.
Claims20
A method for forming a field effect transistor (FET), the method comprising:
- providing a substrate;
- etching the substrate to form a protrusion on a surface of the substrate;
- forming isolation features on the substrate;
- doping a portion of the substrate adjacent to the protrusion to form a drain region between the isolation features, including doping a lower portion of the protrusion to form a raised drain region;
- forming a first isolation dielectric layer over the drain region;
- forming a gate stack having a planar portion and a gating surface over the drain region, the planar portion being parallel to the surface of the substrate and having a sidewall, the gating surface wrapping around a middle portion of the protrusion and overlapping with the raised drain region;
- forming a second isolation dielectric layer over the planar portion of the gate stack and the raised drain region;
- recessing a portion of the gating surface of the gate stack to expose a top portion of the protrusion;
- forming a source region on the top portion of the protrusion with a different doping type than the drain region, the source region overlapping with the gating surface of the gate stack;
- forming a third isolation dielectric layer over the source region, the gate stack and the second isolation dielectric layer;
- forming a drain contact on the drain region and a portion of one of the isolation features together;
- simultaneously with the drain contact formation, forming a gate contact on the planar portion of the gate stack and the sidewall of the planar portion of the gate stack, the gate contact extending through a portion of the isolation dielectric layer;
- and
- forming a source contact on the source region.
11 more elements
A method for forming a field effect transistor (FET), the method comprising:
- providing a substrate having a protrusion structure formed on a planar surface of the substrate, the protrusion structure having a top portion, a middle portion, and a bottom portion;
- forming an isolation structure in the substrate;
- forming a drain region in the substrate and in the bottom portion of the protrusion structure, wherein the drain region has a first doping type;
- forming a gate structure over the drain region and on a sidewall of the protrusion structure, the gate structure surrounding the protrusion structure and having a planar region extending away from the protrusion structure and having a sidewall;
- forming a source region in the top portion of the protrusion structure, wherein the source region has a second doping type that is opposite the first doping type;
- forming a drain contact contacting a portion of the drain region and a portion of the isolation structure;
- forming a gate contact contacting a portion of the planar region of the gate structure and a portion of the sidewall of the planar region of the gate structure;
- and
- forming a source contact contacting the source region.
6 more elements
A method for forming a field effect transistor (FET), the method comprising:
- receiving a substrate, the substrate having a protrusion formed thereon;
- forming an isolation structure in the substrate, the isolation structure surrounding the protrusion;
- forming a drain feature in the substrate, the drain feature extending into a bottom portion of the protrusion, wherein the drain feature has a first doping type;
- forming a source feature in a top portion of the protrusion, wherein the source feature has a second doping type that is opposite the first doping type;
- forming a gate feature on a sidewall of the protrusion such that the gate feature is in contact with the top portion of the protrusion and the bottom portion of the protrusion, the gate feature having a planar portion extending laterally away from the protrusion parallel to the drain feature and having a sidewall;
- forming a source contact on the source feature;
- forming a drain contact on the drain feature and overlapping with the isolation structure;
- and
- forming a gate contact on the planar portion of the gate feature and in contact with the sidewall of the gate feature.
6 more elements
Dependencies are inferred from the claim text.