Abstract: Structures and processes are provided that can be used for effectively integrating different transistor designs across a process platform. In particular, a bifurcated process is provided in which dopants and other processes for forming some transistor types may be performed prior to STI or other device isolation processes, and other devices may be formed thereafter. Thus, doping and other steps and their sequence with respect to the STI process can be selected to be STI-first or STI-last, depending on the device type to be manufactured, the range of device types that are manufactured on the same wafer or die, or the range of device types that are planned to be manufactured using the same or similar mask sets.

Abstract: A semiconductor device includes core transistors for forming a logic circuit, and I/O transistors for forming an input/output circuit. A distance from the main surface to a lowermost part of an n-type impurity region NR of the I/O n-type transistor is longer than that from the main surface to a lowermost part of an n-type impurity region NR of the core n-type transistor. A distance from the main surface to a lowermost part of a p-type impurity region PR of the I/O p-type transistor is longer than that from the main surface to a lowermost part of a p-type impurity region of the core p-type transistor. A distance from the main surface to the lowermost part of the n-type impurity region of the I/O n-type transistor is longer than that from the main surface to the lowermost part of the p-type impurity region of the I/O p-type transistor.

Abstract: a method comprises forming a hardmask over one or more gate structures. The method further comprises forming a photoresist over the hardmask. The method further comprises forming an opening in the photoresist over at least one of the gate structures. The method further comprises stripping the hardmask that is exposed in the opening and which is over the at least one of the gate structures. The method further comprises removing the photoresist. The method further comprises providing a halo implant on a side of the at least one of the gate structures.

Abstract: Methods for semiconductor fabrication include forming a well in a semiconductor substrate. A pocket is formed within the well, the pocket having an opposite doping polarity as the well to provide a p-n junction between the well and the pocket. Defects are created at the p-n junction such that a leakage resistance of the p-n junction is decreased.

Abstract: In an embodiment of the invention, a method of forming an NMOS (n-type metal-oxide semiconductor) transistor is disclosed. A dual mask pattern is used to ion-implant source/drain regions of the NMOS transistor. The first mask allows first doses of As (arsenic), P (phosphorous) and N (Nitrogen) to be ion-implanted. After these doses are ion-implanted, a high temperature (900-1050 C) spike anneal is performed to activate the formed source/drains. A second mask allows a second dose of phosphorus to be implanted in the source/drain regions. The second dose of the phosphorus is typically higher than the first dose of phosphorus. The second dose of phosphorus lowers the Rsd (resistance of the source and drain regions) and dopes n-type poly-silicon blocks.

Abstract: A composite semiconductor structure and method of forming the same are provided. The composite semiconductor structure includes a first silicon-containing compound layer comprising an element selected from the group consisting essentially of germanium and carbon; a silicon layer on the first silicon-containing compound layer, wherein the silicon layer comprises substantially pure silicon; and a second silicon-containing compound layer comprising the element on the silicon layer. The first and the second silicon-containing compound layers have substantially lower silicon concentrations than the silicon layer. The composite semiconductor structure may be formed as source/drain regions of metal-oxide-semiconductor (MOS) devices.

Abstract: The present disclosure provides one embodiment of a method forming a p-type field effect transistor (pFET) structure. The method includes forming a mask layer on a semiconductor substrate, the mask layer including an opening that exposes a semiconductor region of the semiconductor substrate within the opening; forming a n-type well (n-well) in the semiconductor region by performing an ion implantation of a n-type dopant to the semiconductor substrate through the opening of the mask layer; and performing a germanium (Ge) channel implantation to the semiconductor substrate through the opening of the mask layer, forming a Ge channel implantation region in the n-well.

Abstract: A semiconductor structure comprising a first semiconductor layer, a bulk semiconductor layer, an insulation layer between the first semiconductor layer and the bulk semiconductor layer, a first implanted region that is at least partially within the insulation layer; and a second doped region that is at least partially within the bulk semiconductor layer, wherein the first implanted region has an implant profile that shows a maximum within the insulation layer and a tail extending within the bulk semiconductor layer so as to inhibit the diffusion of a second doping material of the second doped region within the insulation layer.

Abstract: When forming semiconductor devices including transistors with different threshold voltages, the different threshold voltages of transistors of the same conductivity type are substantially defined by performing different halo implantations. As the other implantations performed typically in the same manufacturing step, such as pre-amorphization, source and drain extension implantation and extra diffusion engineering implantations, may be identical for different threshold voltages, these implantations, in addition to a common halo base implantation, may be performed for all transistors of the same conductivity type in a common implantation sequence. Higher threshold voltages of specific transistors may be subsequently achieved by an additional low-dose halo implantation while the other transistors are covered by a resist mask. Thus, the amount of atoms of the implant species in the required resist masks is reduced so that removal of the resist masks is facilitated.

Abstract: In an embodiment of the invention, a method of forming an NMOS (n-type metal-oxide semiconductor) transistor is disclosed. A dual mask pattern is used to ion-implant source/drain regions of the NMOS transistor. The first mask allows first doses of As (arsenic), P (phosphorous) and N (Nitrogen) to be ion-implanted. After these doses are ion-implanted, a high temperature (900-1050 C) spike anneal is performed to activate the formed source/drains. A second mask allows a second dose of phosphorus to be implanted in the source/drain regions. The second dose of the phosphorus is typically higher than the first dose of phosphorus. The second dose of phosphorus lowers the Rsd (resistance of the source and drain regions) and dopes n-type poly-silicon blocks.

Abstract: Semiconductor devices and methods of fabricating the same are provided. An insulating film can be disposed on a semiconductor substrate, and insulating film patterns can be formed opening a plurality of areas with predetermined widths by patterning the insulating film. A plurality of ion implantation areas having a first conductivity type can be formed by implanting impurities into the plurality of open areas, and an oxide film pattern can be formed on each of the ion implantation areas. The insulating film patterns can be removed, and ion implantation areas having a second conductivity type can be formed by implanting impurities using the oxide film pattern as a mask. The semiconductor substrate can be annealed at a high temperature to form deep wells.

Abstract: The invention discloses a manufacture method and structure of a power transistor, comprising a lower electrode, a substrate, a drift region, two first conductive regions, two second conductive regions, two gate units, an isolation structure and an upper electrode. The two second conductive region are between the two first conductive regions and the drift region; the two gate units are on the two second conductive regions; the isolation structure covers the two gate units; the upper electrode covers the isolation structure and connects to the two first conductive regions and the two second conductive regions electrically. When the substrate is of the first conductive type, the structure can be used as MOSFET. When the substrate is of the second conductive type, the structure can be used as IGBT. This structure has a small gate electrode area, which leads to less Qg, Qgd and Rdson and improves device performance.

Abstract: Dark currents within a photosensitive device are reduced through improved implantation of a species during its fabrication. Dark currents can be caused by defects in the photo-diode device, caused during the annealing, implanting or other processing steps used during fabrication. By amorphizing the workpiece in the photo-diode region, the number of defects can be reduced thereby reducing this cause of dark current. Dark current is also caused by stress induced by an adjacent STI, where the stress caused by the liner and fill material exacerbate defects in the workpiece. By amorphizing the sidewalls and bottom surface of the trench, defects created during the etching process can be reduced. This reduction in defects also decreases dark current in the photosensitive device.

Abstract: A method comprising, introducing a dopant type into a semiconductor layer to define a well region of the semiconductor layer, the well region comprising a channel region, and introducing a dopant type into the well region to define a multiple implant region substantially coinciding with the well region but excluding the channel region.

Abstract: Methods of forming self-aligned patterns for performing oppositely doped deep implantations in a semiconductor substrate are disclosed. The semiconductor substrate has implantation and non-implantation regions. The methods include forming a hardmask pattern for a first implantation with a first conductivity-type dopant, depositing an etch stop layer, filling trenches between the hardmask pattern with a sacrificial filler material having a higher wet etch resistance than the hardmask, removing a top portion of the sacrificial filler material and the etch stop layer over a top surface of the hardmask pattern, removing the hardmask pattern in the implantation region by wet etching, and performing a second ion implantation with a second conductivity type dopant opposite of the first conductivity type.

Abstract: An impurity of a first conductivity type is implanted onto a silicon carbide substrate through an opening in a mask layer. First and second films made of first and second materials respectively are formed. It is sensed that etching of the first material is performed during anisotropic etching, and then anisotropic etching is stopped. An impurity of a second conductivity type is implanted onto the silicon carbide substrate through the opening narrowed by the first and second films. Thus, the impurity regions can be formed in an accurately self-aligned manner.

Abstract: A method of tailoring the dopant profile of a workpiece by modulating one or more operating parameters is disclosed. In one embodiment, the workpiece may be a solar cell and the desired dopant profile may include a heavily doped surface region and a highly doped region. These two regions can be generated by varying one or more of the parameters of the ion implanter. For example, the extraction voltage may be changed to affect the energy of the implanted ions. The ionization energy can be changed to affect the species of ions being generated from the source gas. In another embodiment, the source gasses that are ionized may be changed to affect the species being generated. After the implant has been performed, thermal processing is performed which minimizes the diffusion of the ions in the workpiece.

Abstract: A semiconductor device includes a first transistor including a first source/drain region and a first sidewall spacer, and a second transistor including a second source/drain region and a second sidewall spacer, the first sidewall spacer has a first width and the second sidewall spacer has a second width wider than the first width, and the first source/drain region has a first area and the second source/drain region has a second area larger than the first area.

Abstract: Silicon loss prevention in a substrate during transistor device element manufacture is achieved by limiting a number of photoresist mask and chemical oxide layer stripping opportunities during the fabrication process. This can be achieved through the use of a protective layer that remains on the substrate during formation and stripping of photoresist masks used in identifying the implant areas into the substrate. In addition, undesirable reworking steps due to photoresist mask misalignment are eliminated or otherwise have no effect on consuming silicon from the substrate during fabrication of device elements. In this manner, device elements with the same operating characteristics and performance can be consistently made from lot to lot.

Abstract: In order to keep the crystallinity of the semiconductor thin film layer high, a temperature of a semiconductor substrate during hydrogen ion addition treatment is suppressed to lower than or equal to 200° C. In addition, the semiconductor substrate is subjected to plasma treatment while the semiconductor substrate is kept at a temperature of higher than or equal to 100° C. and lower than or equal to 400° C. after the hydrogen ion addition treatment, whereby Si—H bonds which have low contribution to separation of the semiconductor thin film layer can be reduced while Si—H bonds which have high contribution to separation of the semiconductor thin film layer, which are generated by the hydrogen ion addition treatment, are kept.

Abstract: A method of fabricating an electrostatic discharge protection structure includes the following steps. Firstly, a semiconductor substrate is provided. Plural isolation structures, a well region, a first conductive region and a second conductive region are formed in the semiconductor substrate. The well region contains first type conducting carriers. The first conductive region and the second conductive region contain second type conducting carriers. Then, a mask layer is formed on the surface of the semiconductor substrate, wherein a part of the first conductive region is exposed. Then, a first implantation process is performed to implant the second type conducting carriers into the well region by using the mask layer as an implantation mask, so that a portion of the first type conducting carriers of the well region is electrically neutralized and a first doped region is formed under the exposed part of the first conductive region.

Abstract: An improved method of tilting a mask to perform a pattern implant of a substrate is disclosed. The mask has a plurality of apertures, and is placed between the ion source and the substrate. The mask and substrate are tilted at a first angle relative to the incoming ion beam. After the substrate is exposed to the ion beam, the mask and substrate are tilted at a second angle relative to the ion beam and a subsequent implant step is performed. Through the selection of the aperture size and shape, the cross-section of the mask, the distance between the mask and the substrate and the number of implant steps, a variety of implant patterns may be created. In some embodiments, the implant pattern includes heavily doped horizontal stripes with lighter doped regions between the stripes. In some embodiments, the implant pattern includes a grid of heavily doped regions.

Abstract: A method of manufacturing a semiconductor device, the semiconductor device including a MOS transistor, a source electrode and a drain electrode on the MOS transistor each include a first carbon doped silicon layer including carbon at a first carbon concentration and phosphorus at a first phosphorus concentration and a second carbon doped silicon layer over the first silicon carbide layer, which includes phosphorus at a second phosphorus concentration higher than the first phosphorus concentration, and which includes carbon at a second carbon concentration less than or equal to the first carbon concentration.

Abstract: A junction diode array for use in protecting integrated circuits from electrostatic discharge can be fabricated to include symmetric and/or asymmetric junction diodes of various sizes. The diodes can be configured to provide low voltage and current discharge via unencapsulated contacts, or high voltage and current discharge via encapsulated contacts. Use of tilted implants in fabricating the junction diode array allows a single hard mask to be used to implant multiple ion species. Furthermore, a different implant tilt angle can be chosen for each species, along with other parameters, (e.g., implant energy, implant mask thickness, and dimensions of the mask openings) so as to craft the shape of the implanted regions. Isolation regions can be inserted between already formed diodes, using the same implant hard mask if desired. A buried oxide layer can be used to prevent diffusion of dopants into the substrate beyond a selected depth.

Abstract: A system and method for image sensing is disclosed. An embodiment comprises a substrate with a pixel region, the substrate having a front side and a backside. A co-implant process is performed along the backside of the substrate opposing a photosensitive element positioned along the front side of the substrate. The co-implant process utilizes a first pre-amorphization implant process that creates a pre-amorphization region. A dopant is then implanted wherein the pre-amorphization region retards or reduces the diffusion or tailing of the dopants into the photosensitive region. An anti-reflective layer, a color filter, and a microlens may also be formed over the co-implant region.

Abstract: A fin field-effect transistor (FinFET) includes a substrate and a fin structure over the substrate. The fin structure comprises a lightly doped source and drain (LDD) region uniformly beneath a top surface and sidewall surfaces of the fin structure, the LDD region having a depth less than about 25 nm. Another FinFET includes a substrate and a fin structure over the substrate. The fin structure comprises a lightly doped source and drain (LDD) region, and a top surface of the fin structure has a different crystal structure from a sidewall surface of the fin structure. A method of making a FinFET includes forming a fin structure on a substrate. The method further includes performing a pulsed plasma doping on the fin structure to form lightly doped drain (LDD) regions in the fin structure.

Abstract: Methods and devices for forming both high-voltage and low-voltage transistors on a common substrate using a reduced number of processing steps are disclosed. An exemplary method includes forming at least a first high-voltage transistor well and a first low-voltage transistor well on a common substrate separated by an isolation structure extending a first depth into the substrate, using a first mask and first implantation process to simultaneously implant a doping material of a first conductivity type into a channel region of the low-voltage transistor well and a drain region for the high-voltage transistor well.

Abstract: A semiconductor device manufacturing method includes exciting plasma, applying RF power onto a target substrate to generate substrate bias and performing an ion implantation plural times by applying the RF power in the form of pulses.

Abstract: The present invention discloses a semiconductor overlapped PN structure and manufacturing method thereof. The method includes: providing a substrate; providing a first mask to define a P (or N) type well and at least one overlapped region in the substrate; implanting P (or N) type impurities into the P (or N) type well and the at least one overlapped region; providing a second mask having at least one opening to define an N (or P) type well in the substrate, and to define at least one dual-implanted region in the at least one overlapped region; implanting N (or P) type impurities into the N (or P) type well and the at least one dual-implanted region such that the at least one dual-implanted region has P type and N type impurities.

Abstract: A HKMG device with PMOS eSiGe source/drain regions is provided. Embodiments include forming first and second HKMG gate stacks on a substrate, each including a SiO2 cap, forming extension regions at opposite sides of the first HKMG gate stack, forming a nitride liner and oxide spacers on each side of HKMG gate stack; forming a hardmask over the second HKMG gate stack; forming eSiGe at opposite sides of the first HKMG gate stack, removing the hardmask, forming a conformal liner and nitride spacers on the oxide spacers of each of the first and second HKMG gate stacks, and forming deep source/drain regions at opposite sides of the second HKMG gate stack.

Abstract: A stratified photodiode for high resolution CMOS image sensors implemented with STI technology is provided. The photodiode includes a semi-conductive layer of a first conductivity type, multiple doping regions of a second conductivity type, multiple doping regions of the first conductivity type, and a pinning layer. The multiple doping regions of the second conductivity type are formed to different depths in the semi-conductive layer. The multiple doping regions of the first conductivity type are disposed between the multiple doping regions of the second conductivity type and form multiple junction capacitances without full depletion. In particular, the stratified doping arrangement allows the photodiode to have a small size, high charge storage capacity, low dark current, and low operation voltages.

Abstract: A method of ion implantation is disclosed. A beam of ions is accelerated to a first energy level. The beam of ions is decelerated from the first energy level to produce a contamination beam of ions via an ion collision process. The ions of the contamination beam are implanted in a substrate to obtain a selected dopant profile in the substrate.

Abstract: One method of implanting a workpiece involves implanting the workpiece with an n-type dopant in a first region with center and a periphery. The workpiece also is implanted with a p-type dopant in a second region complementary to the first region. This second region also has a center and a periphery. The periphery of the first region and the periphery of the second region at least partially overlap. A dose at the periphery of the first region or second region is less than a dose at the center of the first region or second region. The region of overlap may function as a junction where charge carriers cannot pass.

Abstract: Disclosed herein is a method of forming a semiconductor device. In one example, the method includes forming a gate electrode structure above a semiconducting substrate, wherein the gate electrode structure includes a gate insulation layer, a gate electrode, a first sidewall spacer positioned proximate the gate electrode, and a gate cap layer, and forming an etch stop layer above the gate cap layer and above the substrate proximate the gate electrode structure. The method further includes forming a layer of spacer material above the etch stop layer, and performing at least one first planarization process to remove the portion of said layer of spacer material positioned above the gate electrode, the portion of the etch stop layer positioned above the gate electrode and the gate cap layer.

Abstract: A method includes: forming a transfer gate on a semiconductor substrate; forming a first ion implantation region on a first side of the transfer gate; forming a second ion implantation region on the first side of the transfer gate such that the second ion implantation region encloses the first ion implantation region; forming a third ion implantation region along a surface of the semiconductor substrate; and forming a floating diffusion region at a second side of the transfer gate.

Abstract: The present invention relates generally to methods for high throughput and controllable creation of high performance semiconductor substrates for use in devices such as high sensitivity photodetectors, imaging arrays, high efficiency solar cells and the like, to semiconductor substrates prepared according to the methods, and to an apparatus for performing the methods of the invention.

Abstract: Integrated circuits that include SRAM cells having additional read stacks and methods for their fabrication are provided. In accordance with one embodiment a method for fabricating such an integrated circuit includes forming a plurality of SRAM cells in and on a semiconductor substrate, each of the plurality of SRAM cells including a read pull down transistor and a read pass gate transistor. First conductivity-determining impurity ions are implanted to establish a first threshold voltage in each of the read pull down transistors; and second conductivity-determining impurity ions are implanted to establish a second threshold voltage different than the first threshold voltage in each of the read pass gate transistors.

Abstract: Semiconductor device structures and related fabrication methods are provided. An exemplary method of fabricating a semiconductor device on a doped region of semiconductor material having a first conductivity type involves forming a first region having a second conductivity type within the doped region, forming a body region having the first conductivity type overlying the first region, and forming a drift region having the second conductivity type within the doped region, wherein at least a portion of the drift region abuts at least a portion of the first region. In one embodiment, the dopant concentration of the first region is less than the dopant concentration of the body region and different from the dopant concentration of the drift region.

Abstract: A method of manufacturing a semiconductor device is disclosed. A p-type substrate is doped to form an N-well in a selected portion of a p-type substrate adjacent an anode region of the substrate. A p-type doped region is formed in the anode region of the p-type substrate. The p-type doped region and the N-well form a p-n junction.

Abstract: An exemplary semiconductor device comprises a through silicon via penetrating a semiconductor substrate including a circuit pattern on one side of the substrate, a first doped layer formed in the other side, and a bump connected with the through silicon via.

Abstract: It is an object to provide an epitaxial silicon wafer that is provided with an excellent gettering ability in which a polysilicon layer is formed on the rear face side of a silicon crystal substrate into which phosphorus (P) and germanium (Ge) have been doped. A silicon epitaxial layer is grown by a CVD method on the surface of a silicon crystal substrate into which phosphorus and germanium have been doped at a high concentration. After that, a PBS forming step for growing a polysilicon layer is executed on the rear face side of a silicon crystal substrate. By the above steps, the number of LPDs (caused by an SF) that occur on the surface of the epitaxial silicon wafer due to the SF can be greatly reduced.

Abstract: The object to provide a semiconductor device comprising a highly-integrated SGT-based CMOS inverter circuit is achieved by forming an inverter which comprises: a first transistor including; an first island-shaped semiconductor layer; a first gate insulating film; a gate electrode; a first first-conductive-type high-concentration semiconductor layer arranged above the first island-shaped semiconductor layer; and a second first-conductive-type high-concentration semiconductor layer arranged below the first island-shaped semiconductor layer, and a second transistor including; a second gate insulating film surrounding a part of the periphery of the gate electrode; a second semiconductor layer in contact with a part of the periphery of the second gate insulating film; a first second-conductive-type high-concentration semiconductor layer arranged above the second semiconductor layer; and a second second-conductive-type high-concentration semiconductor layer arranged below the second semiconductor layer.

Abstract: In an ion implantation method, ion implantation into a substrate is performed while changing a relative positional relation between an ion beam and the substrate. A first ion implantation process in which a uniform dose amount distribution is formed within the substrate and a second ion implantation process in which a non-uniform dose amount distribution is formed within the substrate are performed in a predetermined order. Moreover, a cross-sectional size of an ion beam irradiated on the substrate during the second ion implantation process is set smaller than a cross-sectional size of an ion beam irradiated on the substrate during the first ion implantation process.

Abstract: Methods of forming self-aligned patterns for performing oppositely doped deep implantations in a semiconductor substrate are disclosed. The semiconductor substrate has implantation and non-implantation regions. The methods include forming a hardmask pattern for a first implantation with a first conductivity-type dopant, depositing an etch stop layer, filling trenches between the hardmask pattern with a sacrificial filler material having a higher wet etch resistance than the hardmask, removing a top portion of the sacrificial filler material and the etch stop layer over a top surface of the hardmask pattern, removing the hardmask pattern in the implantation region by wet etching, and performing a second ion implantation with a second conductivity type dopant opposite of the first conductivity type.

Abstract: A method of implanting ions into a workpiece without the formation of junctions, which impact the performance of the workpiece, is disclosed. To counteract the effect of dopant being implanted into the edge of the workpiece, components made of material having an opposite conductivity are placed near the workpiece. As ions from the beam strike these components, ions from the material are sputtered. These ions have the opposite conductivity as the implanted ions, and therefore inhibit the formation of junctions.

Abstract: A method of manufacturing a semiconductor device having a twin well structure is provided. The method includes ion-implanting of a first conductivity type impurity in a first region and a second region of a semiconductor substrate, the first and second regions being located adjacent to each other; forming a first resist pattern to cover the first region of the semiconductor substrate and to expose the second region of the semiconductor substrate; ion-implanting of a second conductivity type impurity at a higher concentration compared to the first conductivity type impurity in the second region of the semiconductor substrate, with the first resist pattern being used as a mask; and thermal-diffusing the first conductivity type of impurity and the second conductivity type of impurity.

Abstract: To provide a semiconductor device and a method of manufacturing the same capable of suppressing, when a plurality of MIS transistors having different absolute values of threshold voltage is used, the reduction of the drive current of a MIS transistor having a greater absolute value of threshold voltage. The threshold voltage of a second nMIS transistor is greater than the threshold voltage of a first nMIS transistor and the sum of the concentration of lanthanum atom and the concentration of magnesium atom in a second nMIS high-k film included in the second nMIS transistor is lower than the sum of the concentration of lanthanum atom and the concentration of magnesium atom in a first nMIS high-k film included in the first nMIS transistor.

Abstract: An integrated circuit structure having an LDMOS transistor and a CMOS transistor includes a p-type substrate having a surface, an n-well implanted in the substrate, the first n-well providing a CMOS n-well, a CMOS transistor including a CMOS source with a first p+ region implanted in the n-well, a CMOS drain with a second p+ region implanted in the n-well, and a CMOS gate between the first p+ region and the second p+ region, and an LDMOS transistor including an LDMOS source with an LDMOS source including a p-body implanted in the n-well, a third p+ region implanted in the p-body, and a first n+ region implanted in the p-body, an LDMOS drain including an n-doped shallow drain implanted in the n-well, and a second n+ region implanted in the n-doped shallow drain, and an LDMOS gate between the third p+ region and the second n+ region.

Abstract: Methods and apparatus for implanting a dopant material are provided herein. In some embodiments, a method of processing a substrate disposed within a process chamber may include (a) implanting a dopant material into a surface of the substrate to form a doped layer in the substrate and an elemental dopant layer atop the doped layer; (b) removing at least some of the elemental dopant layer from atop the surface of the substrate; and (c) implanting the dopant material into the doped layer of the substrate; wherein (a)-(c) are performed without removing the substrate from the process chamber; and wherein (a)-(c) are repeated until at least one of a desired dopant implantation depth or a desired dopant implantation density is achieved.

Abstract: A method for fabricating field effect transistors using carbon doped silicon layers to substantially reduce the diffusion of a doped screen layer formed below a substantially undoped channel layer includes forming an in-situ epitaxial carbon doped silicon substrate that is doped to form the screen layer in the carbon doped silicon substrate and forming the substantially undoped silicon layer above the carbon doped silicon substrate. The method may include implanting carbon below the screen layer and forming a thin layer of in-situ epitaxial carbon doped silicon above the screen layer. The screen layer may be formed either in a silicon substrate layer or the carbon doped silicon substrate.