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: 20070235759
    Abstract: An integration scheme for providing Si gates for nFET devices and SiGe gates for pFET devices on the same semiconductor substrate is provided. The integration scheme includes first providing a material stack comprising, from bottom to top, a gate dielectric, a Si film, and a hard mask on a surface of a semiconductor substrate that includes at least one nFET device region and at least one pFET device region. Next, the hard mask is selectively removed from the material stack in the at least one pFET device region thereby exposing the Si film. The exposed Si film is then converted into a SiGe film and thereafter at least one nFET device is formed in the least one nFET device region and at least one pFET device is formed in the at least one pFET device region. In accordance with the present invention, the least one nFET device includes a Si gate and the at least one pFET includes a SiGe gate.
    Type: Application
    Filed: April 11, 2006
    Publication date: October 11, 2007
    Applicant: International Business Machines Corporation
    Inventors: William Henson, Yaocheng Liu, Alexander Reznicek, Kern Rim, Devendra Sadana
  • Publication number: 20070238276
    Abstract: A method to control the poly-Si depletion effect in CMOS structures utilizing a gas phase doping process which is capable of providing a high concentration of dopant atoms at the gate dielectric/poly-Si interface is provided. The present invention also provides CMOS structure including, for example, nFETs and/or pFETs, that are fabricated utilizing the gas phase doping technique described herein.
    Type: Application
    Filed: April 11, 2006
    Publication date: October 11, 2007
    Applicant: International Business Machines Corporation
    Inventors: Yaocheng Liu, Alexander Reznicek, Devendra Sadana
  • Publication number: 20070228484
    Abstract: A method for fabricating a semiconductor substrate includes epitaxially growing an elemental semiconductor layer on a compound semiconductor substrate. An insulating layer is deposited on top of the elemental semiconductor layer, so as to form a first substrate. The first substrate is wafer bonded onto a monocrystalline Si substrate, such that the insulating layer bonds with the monocrystalline Si substrate. A semiconductor device includes a monocrystalline substrate, and a dielectric layer formed on the monocrystalline substrate. A semiconductor compound is formed on the dielectric layer and an elemental semiconductor material formed in proximity of the semiconductor compound and lattice-matched to the semiconductor compound.
    Type: Application
    Filed: June 13, 2007
    Publication date: October 4, 2007
    Inventors: STEVEN KOESTER, Devendra Sadana, Ghavam Shahidi
  • Publication number: 20070228473
    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: June 5, 2007
    Publication date: October 4, 2007
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Diane Boyd, Bruce Doris, Meikei Ieong, Devendra Sadana
  • Publication number: 20070218597
    Abstract: A structure and method for controlling the behavior of dislocations in strained semiconductor layers is described incorporating a graded alloy region to provide a strain gradient to change the slope or curvature of a dislocation propagating upwards or gliding in the semiconductor layer in the proximity of the source and drain of a MOSFET. The upper surface of the strained semiconductor layer may be roughened and/or contain a dielectric layer or silicide which may be patterned to trap the upper end of dislocations in selected surface areas. The invention solves the problem of dislocation segments passing through both the source and drain of a MOSFET creating leakage currents or shorts therebetween.
    Type: Application
    Filed: March 15, 2006
    Publication date: September 20, 2007
    Applicant: International Business Machines Corporation
    Inventors: Stephen Bedell, Joel DeSouza, Devendra Sadana, Klaus Schwarz, Alexander Reznicek
  • Publication number: 20070164358
    Abstract: A semiconducting material that has all the advantages of prior art SOI substrates including, for example, low parasitic capacitance and leakage, without having floating body effects is provided. More specifically, the present invention provides a Semiconductor-on-Pores (SOP) material that includes a top semiconductor layer and a bottom semiconductor layer, wherein the semiconductor layers are separated in at least one region by a porous semiconductor material. Semiconductor structures including the SOP material as a substrate as well as a method of fabricating the SOP material are also provided. The method includes forming a p-type region with a first semiconductor layer, converting the p-type region to a porous semiconductor material, sealing the upper surface of the porous semiconductor material by annealing, and forming a second semiconductor layer atop the porous semiconductor material.
    Type: Application
    Filed: January 17, 2006
    Publication date: July 19, 2007
    Applicant: International Business Machines Corporation
    Inventors: Joel de Souza, Keith Fogel, Brian Greene, Devendra Sadana, Haining Yang
  • Publication number: 20070164356
    Abstract: A strained (tensile or compressive) semiconductor-on-insulator material is provided in which a single semiconductor wafer and a separation by ion implantation of oxygen process are used. The separation by ion implantation of oxygen process, which includes oxygen ion implantation and annealing creates, a buried oxide layer within the material that is located beneath the strained semiconductor layer. In some embodiments, a graded semiconductor buffer layer is located beneath the buried oxide layer, while in other a doped semiconductor layer including Si doped with at least one of B or C is located beneath the buried oxide layer.
    Type: Application
    Filed: January 13, 2006
    Publication date: July 19, 2007
    Applicant: International Business Machines Corporation
    Inventors: Thomas Adam, Stephen Bedell, Joel de Souza, Keith Fogel, Alexander Reznicek, Devendra Sadana, Ghavam Shahidi
  • Publication number: 20070161214
    Abstract: A method of forming a high k gate stack (dielectric constant of greater than that of silicon dioxide) on a surface of a III-V compound semiconductor, such GaAs, is provided. The method includes subjecting a III-V compound semiconductor material to a precleaning process which removes native oxides from a surface of the III-V compound semiconductor material; forming a semiconductor, e.g., amorphous Si, layer in-situ on the cleaned surface of the III-V compound semiconductor material; and forming a dielectric material having a dielectric constant that is greater than silicon dioxide on the semiconducting layer. In some embodiments, the semiconducting layer is partially or completely converted into a layer including at least a surface layer that is comprised of AOxNy prior to forming the dielectric material. In accordance with the present invention, A is a semiconducting material, preferably Si, x is 0 to 1, y is 0 to 1 and x and y are both not zero.
    Type: Application
    Filed: January 6, 2006
    Publication date: July 12, 2007
    Applicant: International Business Machines Corporation
    Inventors: Jean Fompeyrine, Edward Kiewra, Steven Koester, Devendra Sadana, David Webb
  • Publication number: 20070128840
    Abstract: A method of forming a silicon germanium on insulator (SGOI) structure. A SiGe layer is deposited on an SOI wafer. Thermal mixing of the SiGe and Si layers is performed to form a thick SGOI with high relaxation and low stacking fault defect density. The SiGe layer is then thinned to a desired final thickness. The Ge concentration, the amount of relaxation, and stacking fault defect density are unchanged by the thinning process. A thin SGOI film is thus obtained with high relaxation and low stacking fault defect density. A layer of Si is then deposited on the thin SGOI wafer. The method of thinning includes low temperature (550° C.-700° C.) HIPOX or steam oxidation, in-situ HCl etching in an epitaxy chamber, or CMP. A rough SiGe surface resulting from HIPOX or steam oxidation thinning is smoothed with a touch-up CMP, in-situ hydrogen bake and SiGe buffer layer during strained Si deposition, or heating the wafer in a hydrogen environment with a mixture of gases HCl, DCS and GeH4.
    Type: Application
    Filed: January 16, 2004
    Publication date: June 7, 2007
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Huajie Chen, Stephen Bedell, Devendra Sadana, Dan Mocuta
  • Publication number: 20070122634
    Abstract: A substrate for a semiconductor device is disclosed including, in one embodiment, a plurality of semiconductor-on-insulator (SOI) wafers bonded to one another in a single stack. A distal end of the stack includes a first SOI region with a first semiconductor layer having a thickness and a first surface orientation. A surface of the single stack may further include a non-SOI region and/or at least one second SOI region. The non-SOI region may include bulk silicon that extends through all of the insulator layers of the single stack and has a thickness different than that of the first silicon layer. Each second SOI region has a second semiconductor layer having a thickness different than that of the first semiconductor layer and/or a different surface orientation than the first surface orientation. The substrate thus allows formation of different devices on optimal substrate regions that may include different surface orientations and/or different thicknesses and/or different bulk or SOI structures.
    Type: Application
    Filed: November 18, 2005
    Publication date: May 31, 2007
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Junedong Lee, Devendra Sadana, Dominic Schepis, Ghavam Shahidi
  • Publication number: 20070111463
    Abstract: A cost efficient and manufacturable method of fabricating strained semiconductor-on-insulator (SSOI) substrates is provided that avoids wafer bonding. The method includes growing various epitaxial semiconductor layers on a substrate, wherein at least one of the semiconductor layers is a doped and relaxed semiconductor layer underneath a strained semiconductor layer; converting the doped and relaxed semiconductor layer into a porous semiconductor via an electrolytic anodization process, and oxidizing to convert the porous semiconductor layer into a buried oxide layer. The method provides a SSOI substrate that includes a relaxed semiconductor layer on a substrate; a high-quality buried oxide layer on the relaxed semiconductor layer; and a strained semiconductor layer on the high-quality buried oxide layer. In accordance with the present invention, the relaxed semiconductor layer and the strained semiconductor layer have identical crystallographic orientations.
    Type: Application
    Filed: January 6, 2007
    Publication date: May 17, 2007
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Thomas Adam, Stephen Bedell, Joel de Souza, Keith Fogel, Alexander Reznicek, Devendra Sadana, Ghavam Shahidi
  • Publication number: 20070105350
    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: January 2, 2007
    Publication date: May 10, 2007
    Applicant: International Business Machines Corporation
    Inventors: Stephen Bedell, Huajie Chen, Anthony Domenicucci, Keith Fogel, Devendra Sadana
  • Publication number: 20070090487
    Abstract: A method that allows for uniform, simultaneous epitaxial growth of a semiconductor material on dissimilarly doped semiconductor surfaces (n-type and p-type) that does not impart substrate thinning via a novel surface preparation scheme, as well as a structure that results from the implementation of this scheme into the process integration flow for integrated circuitry are provided. The method of the present invention can by used for the selective or nonselective epitaxial growth of semiconductor material from the dissimilar surfaces.
    Type: Application
    Filed: October 26, 2005
    Publication date: April 26, 2007
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Katherina Babich, Bruce Doris, David Medeiros, Devendra Sadana
  • Publication number: 20060275961
    Abstract: Methods of forming a strained Si-containing hybrid substrate are provided as well as the strained Si-containing hybrid substrate formed by the methods. In the methods of the present invention, a strained Si layer is formed overlying a regrown semiconductor material, a second semiconducting layer, or both. In accordance with the present invention, the strained Si layer has the same crystallographic orientation as either the regrown semiconductor layer or the second semiconducting layer. The methods provide a hybrid substrate in which at least one of the device layers includes strained Si.
    Type: Application
    Filed: July 25, 2006
    Publication date: December 7, 2006
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Kevin Chan, Meikei Ieong, Alexander Reznicek, Devendra Sadana, Leathen Shi, Min Yang
  • Publication number: 20060249790
    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: July 6, 2006
    Publication date: November 9, 2006
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Tze-chiang Chen, Guy Cohen, Alexander Reznicek, Devendra Sadana, Ghavam Shahidi
  • Publication number: 20060244068
    Abstract: Hybrid orientation substrates allow the fabrication of complementary metal oxide semiconductor (CMOS) circuits in which the n-type field effect transistors (nFETs) are disposed in a semiconductor orientation which is optimal for electron mobility and the p-type field effect transistors (pFETs) are disposed in a semiconductor orientation which is optimal for hole mobility. This invention discloses that the performance advantages of FETs formed entirely in the optimal semiconductor orientation may be achieved by only requiring that the device's channel be disposed in a semiconductor with the optimal orientation. A variety of new FET structures are described, all with the characteristic that at least some part of the FET's channel has a different orientation than at least some part of the FET's source and/or drain. Hybrid substrates into which these new FETs might be incorporated are described along with their methods of making.
    Type: Application
    Filed: April 27, 2005
    Publication date: November 2, 2006
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Joel Desouza, Devendra Sadana, Katherine Saenger, Chun-yung Sung, Min Yang, Haizhou Yin
  • Publication number: 20060211184
    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: May 18, 2006
    Publication date: September 21, 2006
    Inventors: Diane Boyd, Bruce Doris, Meikei Ieong, Devendra Sadana
  • Publication number: 20060172505
    Abstract: A method for fabricating a semiconductor substrate includes epitaxially growing an elemental semiconductor layer on a compound semiconductor substrate. An insulating layer is deposited on top of the elemental semiconductor layer, so as to form a first substrate. The first substrate is wafer bonded onto a monocrystalline Si substrate, such that the insulating layer bonds with the monocrystalline Si substrate. A semiconductor device includes a monocrystalline substrate, and a dielectric layer formed on the monocrystalline substrate. A semiconductor compound is formed on the dielectric layer and an elemental semiconductor material formed in proximity of the semiconductor compound and lattice-matched to the semiconductor compound.
    Type: Application
    Filed: January 31, 2005
    Publication date: August 3, 2006
    Inventors: Steven Koester, Devendra Sadana, Ghavam Shahidi
  • Publication number: 20060154442
    Abstract: The present invention provides a method for removing or reducing the thickness of ultrathin interfacial oxides remaining at Si—Si interfaces after silicon wafer bonding. In particular, the invention provides a method for removing ultrathin interfacial oxides remaining after hydrophilic Si—Si wafer bonding to create bonded Si—Si interfaces having properties comparable to those achieved with hydrophobic bonding. Interfacial oxide layers of order of about 2 to about 3 nm are dissolved away by high temperature annealing, for example, an anneal at 1300°-1330° C. for 1-5 hours. The inventive method is used to best advantage when the Si surfaces at the bonded interface have different surface orientations, for example, when a Si surface having a (100) orientation is bonded to a Si surface having a (110) orientation. In a more general aspect of the invention, the similar annealing processes may be used to remove undesired material disposed at a bonded interface of two silicon-containing semiconductor materials.
    Type: Application
    Filed: January 7, 2005
    Publication date: July 13, 2006
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Joel de Souza, John Ott, Alexander Reznicek, Devendra Sadana, Katherine Saenger
  • Publication number: 20060154429
    Abstract: The present invention provides a method for forming low-defect density changed-orientation Si by amorphization/templated recrystallization (ATR) processes in which regions of Si having a first crystal orientation are amorphized by ion implantation and then recrystallized into the orientation of a template layer having a different orientation. More generally, the invention relates to the high temperature annealing conditions needed to eliminate the defects remaining in Si-containing single crystal semiconductor materials formed by ion-implant-induced amorphization and templated recrystallization from a layer whose orientation may be the same or different from the amorphous layer's original orientation. The key component of the inventive method is a thermal treatment for minutes to hours in the the temperature range 1250-1330° C. to remove the defects remaining after the initial recrystallization anneal.
    Type: Application
    Filed: January 7, 2005
    Publication date: July 13, 2006
    Applicant: International Business Machines Corporation
    Inventors: Joel de Souza, Keith Fogel, John Ott, Devendra Sadana, Katherine Saenger