Patents by Inventor Devendra Sadana

Devendra Sadana has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20050148161
    Abstract: The invention forms an epitaxial silicon-containing layer on a silicon germanium, patterned strained silicon, or patterned thin silicon-on-insulator surface and avoids creating a rough surface upon which the epitaxial silicon-containing layer is grown. In order to avoid creating the rough surface, the invention first performs a hydrofluoric acid etching process on the silicon germanium, patterned strained silicon, or patterned thin silicon-on-insulator surface. This etching process removes most of oxide from the surface, and leaves a first amount of oxygen (typically 1×1013-1×1015/cm2 of oxygen) on the silicon germanium, patterned strained silicon, or patterned thin silicon-on-insulator surface.
    Type: Application
    Filed: January 2, 2004
    Publication date: July 7, 2005
    Inventors: Huajie Chen, Dan Mocuta, Richard Murphy, Stephan Bedell, Devendra Sadana
  • Publication number: 20050130424
    Abstract: A method of forming a relaxed SiGe-on-insulator substrate having enhanced relaxation, significantly lower defect density and improved surface quality is provided. The method includes forming a SiGe alloy layer on a surface of a first single crystal Si layer. The first single crystal Si layer has an interface with an underlying barrier layer that is resistant to Ge diffusion. Next, ions that are capable of forming defects that allow mechanical decoupling at or near said interface are implanted into the structure and thereafter the structure including the implanted ions is subjected to a heating step which permits interdiffusion of Ge throughout the first single crystal Si layer and the SiGe layer to form a substantially relaxed, single crystal and homogeneous SiGe layer atop the barrier layer. SiGe-on-insulator substrates having the improved properties as well as heterostructures containing the same are also provided.
    Type: Application
    Filed: November 5, 2004
    Publication date: June 16, 2005
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Stephen Bedell, Keith Fogel, Devendra Sadana
  • Publication number: 20050116289
    Abstract: The present invention provides a thin channel MOSFET having low external resistance. In broad terms, a silicon-on-insulator structure comprising a SOI layer located atop a buried insulating layer, said SOI layer having a channel region which is thinned by the presence of an underlying localized oxide region that is located on top of and in contact with said buried insulating layer; and a gate region located atop said SOI layer, wherein said localized oxide region is self-aligned with the gate region. A method for forming the inventive MOSFET is also provided comprising forming a dummy gate region atop a substrate; implanting oxide forming dopant through said dummy gate to create a localized oxide region in a portion of the substrate aligned to the dummy gate region that thins a channel region; forming source/drain extension regions abutting said channel region; and replacing the dummy gate with a gate conductor.
    Type: Application
    Filed: December 2, 2003
    Publication date: June 2, 2005
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Diane Boyd, Bruce Doris, Meikei Ieong, Devendra Sadana
  • Publication number: 20050118826
    Abstract: The present invention comprises a method for forming an ultra-thin channel MOSFET and the ultra-thin channel MOSFET produced therefrom. Specifically, the method comprises providing an SOI substrate having a buried insulating layer underlying an SOI layer; forming a pad stack atop the SOI layer; forming a block mask having a channel via atop the pad stack; providing a localized oxide region in the SOI layer on top of the buried insulating layer thereby thinning a portion of the SOI layer, the localized oxide region being self-aligned with the channel via; forming a gate in the channel via; removing at least the block mask; and forming source/drain extensions in the SOI layer abutting the thinned portion of the SOI layer. Providing the localized oxide region further comprises implanting oxygen dopant through the channel via into a portion of the SOI layer; and annealing the dopant to create the localized oxide region.
    Type: Application
    Filed: December 2, 2003
    Publication date: June 2, 2005
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Diane Boyd, Bruce Doris, Meikei Ieong, Devendra Sadana
  • Publication number: 20050095803
    Abstract: A method of forming a substantially relaxed, high-quality SiGe-on-insulator substrate material using SIMOX and Ge interdiffusion is provided. The method includes first implanting ions into a Si-containing substrate to form an implant rich region in the Si-containing substrate. The implant rich region has a sufficient ion concentration such that during a subsequent anneal at high temperatures a barrier layer that is resistant to Ge diffusion is formed. Next, a Ge-containing layer is formed on a surface of the Si-containing substrate, and thereafter a heating step is performed at a temperature which permits formation of the barrier layer and interdiffusion of Ge thereby forming a substantially relaxed, single crystal SiGe layer atop the barrier layer.
    Type: Application
    Filed: November 9, 2004
    Publication date: May 5, 2005
    Applicant: International Business Machines Corporation
    Inventors: Stephen Bedell, Keith Fogel, Devendra Sadana, Ghavam Shahidi
  • Publication number: 20050093100
    Abstract: A method for fabricating germanium-on-insulator (GOI) substrate materials, the GOI substrate materials produced by the method and various structures that can include at least the GOI substrate materials of the present invention are provided. The GOI substrate material include at least a substrate, a buried insulator layer located atop the substrate, and a Ge-containing layer, preferably pure Ge, located atop the buried insulator layer. In the GOI substrate materials of the present invention, the Ge-containing layer may also be referred to as the GOI film. The GOI film is the layer of the inventive substrate material in which devices can be formed.
    Type: Application
    Filed: November 3, 2003
    Publication date: May 5, 2005
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Tze-chiang Chen, Guy Cohen, Alexander Reznicek, Devendra Sadana, Ghavam Shahidi
  • Publication number: 20050090080
    Abstract: Methods for forming a patterned SOI region in a Si-containing substrate is provided which has geometries of about 0.25 ?m or less. Specifically, one method includes the steps of: forming a patterned dielectric mask on a surface of a Si-containing substrate, wherein the patterned dielectric mask includes vertical edges that define boundaries for at least one opening which exposes a portion of the Si-containing substrate; implanting oxygen ions through the at least one opening removing the mask and forming a Si layer on at least the exposed surfaces of the Si-containing substrate; and annealing at a temperature of about 1250° C. or above and in an oxidizing ambient so as to form at least one discrete buried oxide region in the Si-containing substrate. In one embodiment, the mask is not removed until after the annealing step; and in another embodiment, the Si-containing layer is formed after annealing and mask removal.
    Type: Application
    Filed: November 19, 2004
    Publication date: April 28, 2005
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Keith Fogel, Mark Hakey, Steven Holmes, Devendra Sadana, Ghavam Shahidi
  • Publication number: 20050082526
    Abstract: Techniques for the fabrication of semiconductor devices are provided. In one aspect, a layer transfer structure is provided. The layer transfer structure comprises a carrier substrate having a porous region with a tuned porosity in combination with an implanted species defining a separation plane therein. In another aspect, a method of forming a layer transfer structure is provided. In yet another aspect, a method of forming a three dimensional integrated structure is provided.
    Type: Application
    Filed: October 15, 2003
    Publication date: April 21, 2005
    Applicant: International Business Machines Corporation
    Inventors: Stephen Bedell, Keith Fogel, Bruce Furman, Sampath Purushothaman, Devendra Sadana, Anna Topol
  • Publication number: 20050067055
    Abstract: A method of fabricating silicon-on-insulators (SOIs) having a thin, but uniform buried oxide region beneath a Si-containing over-layer is provided. The SOI structures are fabricated by first modifying a surface of a Si-containing substrate to contain a large concentration of vacancies or voids. Next, a Si-containing layer is typically, but not always, formed atop the substrate and then oxygen ions are implanted into the structure utilizing a low-oxygen dose. The structure is then annealed to convert the implanted oxygen ions into a thin, but uniform thermal buried oxide region.
    Type: Application
    Filed: September 30, 2003
    Publication date: March 31, 2005
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Kwang Choe, Keith Fogel, Siegfried Maurer, Ryan Mitchell, Devendra Sadana
  • Publication number: 20050067294
    Abstract: A method in which a SOI substrate structure is fabricated by oxidation of graded porous Si is provided. The graded porous Si is formed by first implanting a dopant (p- or n-type) into a Si-containing substrate, activating the dopant using an activation anneal step and then anodizing the implanted and activated dopant region in a HF-containing solution. The graded porous Si has a relatively coarse top layer and a fine porous layer that is buried beneath the top layer. Upon a subsequent oxidation step, the fine buried porous layer is converted into a buried oxide, while the coarse top layer coalesces into a solid Si-containing over-layer by surface migration of Si atoms.
    Type: Application
    Filed: September 30, 2003
    Publication date: March 31, 2005
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Kwang Choe, Keith Fogel, Devendra Sadana
  • Publication number: 20050056352
    Abstract: A simple and direct method of forming a SiGe-on-insulator that relies on the oxidation of a porous silicon layer (or region) that is created beneath a Ge-containing layer is provided. The method includes the steps of providing a structure comprising a Si-containing substrate having a hole-rich region formed therein and a Ge-containing layer atop the Si-containing substrate; converting the hole-rich region into a porous region; and annealing the structure including the porous region to provide a substantially relaxed SiGe-on-insulator material.
    Type: Application
    Filed: September 12, 2003
    Publication date: March 17, 2005
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Stephen Bedell, Kwang Choe, Keith Fogel, Devendra Sadana
  • Publication number: 20050045819
    Abstract: A method and calibration standard for fabricating on a single substrate a series of crystalline pairs such that the d-spacing difference between the pairs will generate Moire fringes of the correct spacings to optimally calibrate the magnification settings of an electron microscope over a variety of magnification settings in the range of 5000× to 200,000×. The invention enables the tailoring of Moire fringe spacings to a desired magnification setting for calibration purposes by fabricating a series of patterns on a single substrate whereby each magnification setting is easily calibrated using a specific SGOI structure that is selected by a simple x-y translation across the top plan surface of the SGOI structure, therein eliminating the need for removing calibration samples in and out of the electron microscope. The method and calibration standard may be used for calibrating electron microscopes, such as, scanning transmission electron microscopes and transmission electron microscopes.
    Type: Application
    Filed: August 29, 2003
    Publication date: March 3, 2005
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Stephen Bedell, John Bruley, Anthony Domenicucci, Devendra Sadana
  • Publication number: 20050048778
    Abstract: High-quality, metastable SiGe alloys are formed on SOI substrates having an SOI layer of about 500 ? or less, the SiGe layers can remain substantially fully strained compared to identical SiGe layers formed on thicker SOI substrates and subsequently annealed and/or oxidized at high temperatures. The present invention thus provides a method of ‘frustrating’ metastable strained SiGe layers by growing them on thin, clean and high-quality SOI substrates.
    Type: Application
    Filed: September 3, 2003
    Publication date: March 3, 2005
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Stephen Bedell, Huajie Chen, Keith Fogel, Devendra Sadana
  • Publication number: 20050006704
    Abstract: The present invention provides SOI material which includes a top Si-containing layer which has regions of different thickness as well as a method of fabricating such SOI material. The inventive method includes a step of thinning predetermined regions of the top Si-containing layer by masked oxidation of silicon. SOI IC chips including the inventive SOI material having different types of CMOS devices build thereon as also disclosed.
    Type: Application
    Filed: July 28, 2004
    Publication date: January 13, 2005
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Tak Ning, Devendra Sadana
  • Publication number: 20050003626
    Abstract: A method for forming a semiconductor-on-insulator (SOI) substrate is described incorporating the steps of heating a substrate, implanting oxygen into a heated substrate, cooling the substrate, implanting into a cooled substrate and annealing. The steps of implanting may be at several energies to provide a plurality of depths and corresponding buried damaged regions. Prior to implanting, the step of cleaning the substrate surface and/or forming a patterned mask thereon may be performed. The invention overcomes the problem of raising the quality of buried oxide and its properties such as surface roughness, uniform thickness and breakdown voltage Vbd.
    Type: Application
    Filed: July 22, 2004
    Publication date: January 6, 2005
    Inventors: Stephen Fox, Neena Garg, Kenneth Giewont, Junedong Lee, Siegfried Maurer, Dan Moy, Maurice Norcott, Devendra Sadana
  • Publication number: 20050003229
    Abstract: A method of fabricating high-quality, substantially relaxed SiGe-on-insulator substrate materials which may be used as a template for strained Si is described. A silicon-on-insulator substrate with a very thin top Si layer is used as a template for compressively strained SiGe growth. Upon relaxation of the SiGe layer at a sufficient temperature, the nature of the dislocation motion is such that the strain-relieving defects move downward into the thin Si layer when the buried oxide behaves semi-viscously. The thin Si layer is consumed by oxidation of the buried oxide/thin Si interface. This can be accomplished by using internal oxidation at high temperatures. In this way the role of the original thin Si layer is to act as a sacrificial defect sink during relaxation of the SiGe alloy that can later be consumed using internal oxidation.
    Type: Application
    Filed: July 1, 2003
    Publication date: January 6, 2005
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Stephen Bedell, Huajie Chen, Anthony Domenicucci, Keith Fogel, Devendra Sadana
  • Patent number: 6177289
    Abstract: A monolithic semiconductor optical detector is formed on a substrate having a plurality of substantially parallel trenches etched therein. The trenches are further formed as a plurality of alternating N-type and P-type trench regions separated by pillar regions of the substrate which operate as an I region between the N and P trench regions. First and second contacts are formed on the surface of the substrate and interconnect the N-type trench regions and the P-type trench regions, respectively. Preferably, the trenches are etched with a depth comparable to an optical extinction length of optical radiation to which the detector is responsive.
    Type: Grant
    Filed: December 4, 1998
    Date of Patent: January 23, 2001
    Assignee: International Business Machines Corporation
    Inventors: John Crow, Steve Koester, Daniel M. Kuchta, Dennis L. Rogers, Devendra Sadana, Sandip Tiwari