Split level shallow trench isolation for area efficient body contacts in soi mosfets
AssigneeInternational Business Machines Corporation
InventorsYING LI, Shreesh Narasimha, Werner A. Rausch
Life of this patent
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Abstract
Disclosed is an SOI device on a bulk silicon layer which has an FET region, a body contact region and an STI region. The FET region is made of an SOI layer and an overlying gate. The STI region includes a first STI layer separating the SOI device from an adjacent SOI device. The body contact region includes an extension of the SOI layer, a second STI layer on the extension and a body contact in contact with the extension. The first and second STI layers are contiguous and of different thicknesses so as to form a split level STI.
Claims25
An SOI device comprising:
- an FET region comprising an SOI layer;
- an STI region having a first STI layer separating the SOI device from an adjacent SOI device, the first STI layer having a first thickness;
- a body contact region between the FET region and STI region, the body contact region having an extension of the SOI layer and an overlying second STI layer having a second thickness;
- and
- a body contact in contact with the SOI extension;
- wherein the first thickness is different than the second thickness.
An SOI device comprising:
- a bulk silicon layer;
- an FET region, body contact region and STI region;
- the FET region comprising an SOI layer and a gate on the SOI layer;
- the STI region having a first STI layer separating the SOI device from an adjacent SOI device, the first STI layer having a first thickness;
- the body contact region between the FET region and STI region, the body contact region having an extension of the SOI layer and an overlying second STI layer having a second thickness;
- and
- a body contact in contact with the SOI extension;
- wherein the first thickness is different than the second thickness.
A method of forming an SOI device comprising the steps of:
- forming an FET region comprising an SOI layer;
- forming an STI region having a first STI layer separating the SOI device from an adjacent SOI device, the first STI layer having a first thickness;
- forming a body contact region between the FET region and STI region, the body contact region having an extension of the SOI layer and an overlying second STI layer having a second thickness;
- and
- forming a body contact in contact with the SOI extension;
- wherein the first thickness is different than the second thickness.
A method of forming an SOI device comprising the steps of:
- obtaining a substrate having a bulk silicon layer;
- forming a buried oxide layer on the bulk silicon;
- forming a patterned silicon layer on the buried oxide layer, the patterned silicon layer comprising a first portion and an extension contiguous with the first portion, the extension being thinner than the first portion;
- forming an oxide layer comprising a first STI region on the buried oxide layer and adjacent to the extension and a second STI region on the extension, the first and second STI regions forming a contiguous split level STI such that the first and second STI regions having different thicknesses;
- forming a gate on the first portion of the silicon layer, the gate and first portion of the silicon layer comprising an FET region;
- a body contact in contact with the extension wherein the body contact, extension and second STI layer form a body contact region.
Dependencies are inferred from the claim text.