International Business Machines Corporation

Ka Hing Fung

Dominic Joseph Schepis

H Bernhard Pogge

Atul Champaklal Ajmera

Victor Ku

Percy V Gilbert

A semiconductor device structure includes at least two field effect transistors formed on same substrate, the first field effect transistor includes a spacer having a first width, the second field effect transistor includes a spacer having a second width, the first width being different than said second width. Preferably, the first width is narrower than the second width.

Semiconductor device structure including multiple fets having different spacer widths

A method and structure for fabricating isolation regions on a silicon on insulator (SOI) substrate, wherein the SOI substrate comprises a buried oxide layer and a silicon layer disposed on the buried oxide layer, wherein the silicon layer is less than about 20 nanometers. The method and structure includes a nitride liner layer conformally deposited in the isolation regions.

Method and structure for ultra-thin film SOI isolation

As the silicon-on-insulator field effect transistor (SOI FET) CMOS technology continues migrating towards thinner SOI thicknesses to reduce the parasitic capacitance and improve the short channel effects, it is known that the body resistance of body contacted MOSFETs increases correspondingly. The problem is compounded for strong halo and weak wells device designs for T-shaped or L-shaped BC-MOSFETs. The invention provides a structure and a method that includes an additional well level implant for n-type and p-type devices in selected parts of the extended gate region. A new mask increases the channel doping at the extended gate region to prevent that region from fully depleting and increasing the carrier concentration for lower resistance. Since the physical gate dimensions are usually narrower than the mask dimensions, the mask is slightly offset from the extended gate edge to avoid excessive encroachment into the intrinsic device channel region. The SOI FET includes: a pattern having a first extended region to form a gate for the SOI FET, and a second extended region to isolate the body contact region from the SOI FET; a first sub-region under the first extended region having added doping to adjust the threshold voltage of the SOI FET, the first sub-region defining a gate width of the SOI FET; a second sub-region under the second extended region and an adjoining portion of the first extended gate region to form a low resistance extrinsic body contact region; source and drain regions respectively positioned at each side of the first extended region; and a body contact region adjacent to the second extended region opposite to the SOI FET.

Method of reducing the extrinsic body resistance in a silicon-on-insulator body contacted MOSFET

An innovative MOSFET having a raised source drain (RSD) is constructed prior to implanting source-drain dopants. The RSD structure thus built has a distinct advantage in that the offset from the RSD to the MOSFET channel is fully adjustable to minimize the overlap capacitance in the device. The RSD construction uses a selective epitaxial process to effectively reduce the drain-source resistance. This improvement is even more significant in thin-film SOI technology. Using an RSD, the film outside the channel area thickens which, in turn, reduces the parasitic resistance. The method of constructing such a structure includes the steps of: forming a notch gate on a top surface of a substrate; covering the notch gate and the top surface of the substrate with a conformal dielectric film; etching the dielectric film to expose an upper surface of the notch gate and selected exposed areas of the substrate; selectively growing silicon on the etched surface of the gate notch and on the etched surface of the substrate; implanting doping to form a drain-source area; forming spacers on the vertical walls of the notch gate; and forming a salicide on the notch gate and on the source and drain areas. The MOSFET device may be alternately be built without the formation of spacers.

Method for forming notch gate having self-aligned raised source/drain structure

An assembly consisting of three dimensional stacked SOI chips, and a method of forming such integrated circuit assembly, each of the SOI chips including a handler making mechanical contact to a first metallization pattern making electrical contact to a semiconductor device. The metalized pattern, in turn, contacts a second metallization pattern positioned on an opposite surface of the semiconductor device. The method of fabricating the three-dimensional IC assembly includes the steps of: a) providing a substrate having a third metalized pattern on a first surface of the substrate; b) aligning one of the SOI chips on the first surface of the substrate, by having the second metallization pattern of the SOI chip make electrical contact with the third metalized pattern of the substrate; c) removing the handler from the SOI chip, exposing the first metallization pattern of the SOI chip; d) aligning a second one of the SOI chips with the first SOI chip, having the second metallization pattern of the second SOI chip make electrical contact to the exposed first metallization pattern of the first SOI chip; and e) repeating steps c) and d) for mounting subsequent SOI chips one on top of the other.

Three-dimensional chip stacking assembly

A dual-gate SOI transistor that has the back gate self-aligned to the front gate is formed on an SOI substrate by forming a conventional gate stack having an etch resistant layer on the top; growing epitaxial silicon on the upper surface of the silicon device layer, which leaves apertures on both sides of the gate stack; filling the apertures with etch resistant spacers; defining an etch window bracketing the gate stack and etching alignment trenches down to the bulk silicon. A shallow layer of etch resistant aligning material is deposited on the bottom of the alignment trenches, after which the conventional back end processing as followed of deposition of a supporting layer that supports the layers of the circuit during later processing. The bulk silicon is removed and the back side is patterned to expose the buried oxide below the transistors; an oxide etch leaves a self-aligned backside aperture below the transistors, defined by the etch resistant aligning material. Deposition of a back-side spacer leaves a backside gate aperture that is filled by a metal gate.

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Fishkill, NY, United States of America

Ka Hing Fung