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Devendra K. Sadana, Pleasantville US

Devendra K. Sadana, Pleasantville, NY US

Patent application numberDescriptionPublished
20080203447LOW-TEMPERATURE ELECTRICALLY ACTIVATED GATE ELECTRODE AND METHOD OF FABRICATING SAME - A gate electrode structure is provided, which includes, from bottom to top, an optional, yet preferred metallic layer, a Ge rich-containing layer and a Si rich-containing layer. The sidewalls of the Ge rich-containing layer include a surface passivation layer. The inventive gate electrode structure serves as a low-temperature electrically activated gate electrode of a MOSFET in which the materials thereof as well as the method of fabricating the same are compatible with existing MOSFET fabrication techniques. The inventive gate electrode structure is electrically activated at low processing temperatures (on the order of less than 750° C.). Additionally, the inventive gate electrode structure also minimizes gate-depletion effects, does not contaminate a standard MOS fabrication facility and has sufficiently low reactivity of the exposed surfaces that renders such a gate electrode structure compatible with conventional MOSFET processing steps.08-28-2008
20080217697CONTROL OF POLY-Si DEPLETION IN CMOS VIA GAS PHASE DOPING - 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.09-11-2008
20080246019DEFECT REDUCTION BY OXIDATION OF SILICON - 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.10-09-2008
20080254594STRAINED SILICON CMOS ON HYBRID CRYSTAL ORIENTATIONS - 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.10-16-2008
20080258220ION IMPLANTATION COMBINED WITH IN SITU OR EX SITU HEAT TREATMENT FOR IMPROVED FIELD EFFECT TRANSISTORS - This invention teaches methods of combining ion implantation steps with in situ or ex situ heat treatments to avoid and/or minimize implant-induced amorphization (a potential problem for source/drain (S/D) regions in FETs in ultrathin silicon on insulator layers) and implant-induced plastic relaxation of strained S/D regions (a potential problem for strained channel FETs in which the channel strain is provided by embedded S/D regions lattice mismatched with an underlying substrate layer). In a first embodiment, ion implantation is combined with in situ heat treatment by performing the ion implantation at elevated temperature. In a second embodiment, ion implantation is combined with ex situ heat treatments in a “divided-dose-anneal-in-between” (DDAB) scheme that avoids the need for tooling capable of performing hot implants.10-23-2008
20080277690STRAINED SILICON-ON-INSULATOR BY ANODIZATION OF A BURIED p+ SILICON GERMANIUM LAYER - 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.11-13-2008
20080280416Techniques for Layer Transfer Processing - 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.11-13-2008
20080296622BURIED CHANNEL MOSFET USING III-V COMPOUND SEMICONDUCTORS AND HIGH k GATE DIELECTRICS - A semiconductor-containing heterostructure including, from bottom to top, a III-V compound semiconductor buffer layer, a III-V compound semiconductor channel layer, a III-V compound semiconductor barrier layer, and an optional, yet preferred, III-V compound semiconductor cap layer is provided. The barrier layer may be doped, or preferably undoped. The III-V compound semiconductor buffer layer and the III-V compound semiconductor barrier layer are comprised of materials that have a wider band gap than that of the III-V compound semiconductor channel layer. Since wide band gap materials are used for the buffer and barrier layer and a narrow band gap material is used for the channel layer, carriers are confined to the channel layer under certain gate bias range. The inventive heterostructure can be employed as a buried channel structure in a field effect transistor.12-04-2008
20090067463STRUCTURES HAVING LATTICE-MISMATCHED SINGLE-CRYSTALLINE SEMICONDUCTOR LAYERS ON THE SAME LITHOGRAPHIC LEVEL AND METHODS OF MANUFACTURING THE SAME - A semiconductor substrate containing a single crystalline group IV semiconductor is provided. A single crystalline lattice mismatched group IV semiconductor alloy layer is epitaxially grown on a portion of the semiconductor layer, while another portion of the semiconductor layer is masked. The composition of the lattice mismatched group IV semiconductor alloy layer is tuned to substantially match the lattice constant of a single crystalline compound semiconductor layer, which is subsequently epitaxially grown on the single crystalline lattice mismatched group IV semiconductor alloy layer. Thus, a structure having both the group IV semiconductor layer and the single crystalline compound semiconductor layer is provided on the same semiconductor substrate. Group IV semiconductor devices, such as silicon devices, and compound semiconductor devices, such as GaAs devices having a laser emitting capability, may be formed on the on the same lithographic level of the semiconductor substrate.03-12-2009
20090092810FABRICATION OF SOI WITH GETTERING LAYER - An SOI substrate has a gettering layer of silicon-germanium (SiGe) with 5-10% Ge, and a thickness of approximately 50-1000 nm. Carbon (C) may be added to SiGe to stabilize the dislocation network. The SOI substrate may be a SIMOX SOI substrate, or a bonded SOI substrate, or a seeded SOI substrate. The gettering layer may disposed under a buried oxide (BOX) layer. The gettering layer may be disposed on a backside of the substrate.04-09-2009
20090117720STRAINED SEMICONDUCTOR-ON-INSULATOR BY Si:C COMBINED WITH POROUS PROCESS - A method of fabricating a strained semiconductor-on-insulator (SSOI) substrate is provided. The method includes first providing a structure that includes a substrate, a doped and relaxed semiconductor layer on the substrate, and a strained semiconductor layer on the doped and relaxed semiconductor layer. In the invention, the doped and relaxed semiconductor layer having a lower lattice parameter than the substrate. Next, at least the doped and relaxed semiconductor layer is converted into a buried porous layer and the structure including the buried porous layer is annealed to provide a strained semiconductor-on-insulator substrate. During the annealing, the buried porous layer is converted into a buried oxide layer.05-07-2009
20090134460STRAINED SEMICONDUCTOR-ON-INSULATOR (sSOI) BY A SIMOX METHOD - 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.05-28-2009
20090186455DISPOSABLE METALLIC OR SEMICONDUCTOR GATE SPACER - A disposable spacer is formed directly on or in close proximity to the sidewalls of a gate electrode and a gate dielectric. The disposable spacer comprises a material that scavenges oxygen such as a metal, a metal nitride, or a semiconductor material having high reactivity with oxygen. The disposable gate spacer absorbs any oxygen during subsequent high temperature processing such as a stress memorization anneal. A metal is deposited over, and reacted with, the gate electrode and source and drain regions to form metal semiconductor alloy regions. The disposable gate spacer is subsequently removed selective to the metal semiconductor alloy regions. A porous or non-porous low-k dielectric material is deposited to provide a low parasitic capacitance between the gate electrode and the source and drain regions. The gate dielectric maintains the original dielectric constant since the disposable gate spacer prevents absorption of additional oxygen during high temperature processes.07-23-2009
20090217967POROUS SILICON QUANTUM DOT PHOTODETECTOR - Embodiments of the present invention provide a solar energy converter, which includes a silicon layer having at least two regions of a first and a second conductivity type that form a P-N junction, at least a portion of the silicon layer being porous, and pores in the portion of porous silicon containing a semiconductor material, the semiconductor material being different from silicon; and a first and a second electrode being placed at a bottom and a top surface of the silicon layer respectively. Methods of manufacturing the same are also provided.09-03-2009
20090233079Techniques for Layer Transfer Processing - 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.09-17-2009
20090298258QUASI-HYDROPHOBIC Si-Si WAFER BONDING USING HYDROPHILIC Si SURFACES AND DISSOLUTION OF INTERFACIAL BONDING OXIDE - 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. The two silicon-containing semiconductor materials may be the same or different in surface crystal orientation, microstructure (single-crystal, polycrystalline, or amorphous), and composition.12-03-2009
20090298269STRUCTURES HAVING LATTICE-MISMATCHED SINGLE-CRYSTALLINE SEMICONDUCTOR LAYERS ON THE SAME LITHOGRAPHIC LEVEL AND METHODS OF MANUFACTURING THE SAME - A semiconductor substrate containing a single crystalline group IV semiconductor is provided. A single crystalline lattice mismatched group IV semiconductor alloy layer is epitaxially grown on a portion of the semiconductor layer, while another portion of the semiconductor layer is masked. The composition of the lattice mismatched group IV semiconductor alloy layer is tuned to substantially match the lattice constant of a single crystalline compound semiconductor layer, which is subsequently epitaxially grown on the single crystalline lattice mismatched group IV semiconductor alloy layer. Thus, a structure having both the group IV semiconductor layer and the single crystalline compound semiconductor layer is provided on the same semiconductor substrate. Group IV semiconductor devices, such as silicon devices, and compound semiconductor devices, such as GaAs devices having a laser emitting capability, may be formed on the on the same lithographic level of the semiconductor substrate.12-03-2009
20090302353STRUCTURES CONTAINING ELECTRODEPOSITED GERMANIUM AND METHODS FOR THEIR FABRICATION - Methods for electrodepositing germanium on various semiconductor substrates such as Si, Ge, SiGe, and GaAs are provided. The electrodeposited germanium can be formed as a blanket or patterned film, and may be crystallized by solid phase epitaxy to the orientation of the underlying semiconductor substrate by subsequent annealing. These plated germanium layers may be used as the channel regions of high-mobility channel field effect transistors (FETs) in complementary metal oxide semiconductor (CMOS) circuits.12-10-2009
20100032684ION IMPLANTATION FOR SUPPRESSION OF DEFECTS IN ANNEALED SiGe LAYERS - A method for fabricating substantially relaxed SiGe alloy layers with a reduced planar defect density is disclosed The method of the present invention includes forming a strained Ge-containing layer on a surface of a Si-containing substrate; implanting ions at or below the Ge-containing layer/Si-containing substrate interface and heating to form a substantially relaxed SiGe alloy layer that has a reduced planar defect density. A substantially relaxed SiGe-on-insulator substrate material having a SiGe layer with a reduced planar defect density as well as heterostructures containing the same are also provided.02-11-2010
20100035409CRYSTALLINE SILICON SUBSTRATES WITH IMPROVED MINORITY CARRIER LIFETIME - A method for improving the minority lifetime of silicon containing wafer having metallic contaminants therein is described incorporating annealing at 1200° C. or greater and providing a gaseous ambient of oxygen, an inert gas and a chlorine containing gas such as HCl.02-11-2010
20100112792THICK EPITAXIAL SILICON BY GRAIN REORIENTATION ANNEALING AND APPLICATIONS THEREOF - The invention provides a high temperature (about 1150° C. or greater) annealing process for converting thick polycrystalline Si layers on the order of 1 μm to 40 μm on a single crystal seed layer into thick single crystal Si layers having the orientation of the seed layer, thus allowing production of thick Si films having the quality of single crystal silicon at high rates and low cost of processing. Methods of integrating such high temperature processing into solar cell fabrication are described, with particular attention to process flows in which the seed layer is disposed on a porous silicon release layer. Another aspect pertains to the use of similar high temperature anneals for poly-Si grain growth and grain boundary passivation. A further aspect relates to structures in which these thick single crystal Si films and passivated poly-Si films are incorporated.05-06-2010
20100123205METHOD TO PREVENT SURFACE DECOMPOSITION OF III-V COMPOUND SEMICONDUCTORS - A method of preventing surface decomposition of a III-V compound semiconductor is provided. The method includes forming a silicon film having a thickness from 10 Å to 400 Å on a surface of an III-V compound semiconductor. After forming the silicon film onto the surface of the III-V compound semiconductor, a high performance semiconductor device including, for example, a MOSFET, can be formed on the capped/passivated III-V compound semiconductor. During the MOSFET fabrication, a high k dielectric can be formed on the capped/passivated III-V compound semiconductor and thereafter, activated source and drain regions can be formed into the III-V compound semiconductor.05-20-2010
20100176495LOW COST FABRICATION OF DOUBLE BOX BACK GATE SILICON-ON-INSULATOR WAFERS - A semiconductor wafer structure for integrated circuit devices includes a bulk substrate; a lower insulating layer formed on the bulk substrate; an electrically conductive layer formed on the lower insulating layer; an upper insulating layer formed on the electrically conductive layer, the upper insulating layer formed from a pair of separate insulation layers having a bonding interface therebetween; and a semiconductor layer formed on the upper insulating layer.07-15-2010
20100197118MULTIPLE CRYSTALLOGRAPHIC ORIENTATION SEMICONDUCTOR STRUCTURES - A semiconductor structure includes an epitaxial surface semiconductor layer having a first dopant polarity and a first crystallographic orientation, and a laterally adjacent semiconductor-on-insulator surface semiconductor layer having a different second dopant polarity and different second crystallographic orientation. The epitaxial surface semiconductor layer has a first edge that has a defect and an adjoining second edge absent a defect. Located within the epitaxial surface semiconductor layer is a first device having a first gate perpendicular to the first edge and a second device having a second gate perpendicular to the second edge. The first device may include a performance sensitive logic device and the second device may include a yield sensitive memory device. An additional semiconductor structure includes a further laterally adjacent second semiconductor-on-insulator surface semiconductor layer having the first polarity and the second crystallographic orientation, and absent edge defects, to accommodate yield sensitive devices.08-05-2010
20100261319N-type carrier enhancement in semiconductors - A method for generating n-type carriers in a semiconductor is disclosed. The method includes supplying a semiconductor having an atomic radius. Implanting an n-type dopant species into the semiconductor, which n-type dopant species has a dopant atomic radius. Implanting a compensating species into the semiconductor, which compensating species has a compensating atomic radius. Selecting the n-type dopant species and the compensating species in such manner that the size of the semiconductor atomic radius is inbetween the dopant atomic radius and the compensating atomic radius. A further method is disclosed for generating n-type carriers in germanium (Ge). The method includes setting a target concentration for the carriers, implanting a dose of an n-type dopant species into the Ge, and selecting the dose to correspond to a fraction of the target carrier concentration. Thermal annealing the Ge in such manner as to activate the n-type dopant species and to repair a least a portion of the implantation damage. Repeating the implantation and the thermal annealing until the target n-type carrier concentration has been reached.10-14-2010

Patent applications by Devendra K. Sadana, Pleasantville, NY US