Abstract: An isolation technique is provided for improving the overall planarity of isolation regions relative to adjacent active area silicon mesas. The isolation process results in a trench formed in field regions immediately adjacent the active regions. The trench, however, does not extend entirely across the field region. By preventing large area trenches, substantial dielectric fill material and the problems of subsequent planarization of that fill material is avoided. Accordingly, the present isolation technique does not require conventional fill dielectric normally associated with a shallow trench process. While it achieves the advantages of forming silicon mesas, the present process avoids having to rework dielectric surfaces in large area field regions using conventional sacrificial etchback, block masking and chemical-mechanical polishing. The improved isolation technique hereof utilizes trenches of minimal width etched into the silicon substrate at the periphery of field regions, leaving a field mesa.

Abstract: A semiconductor device having gate oxide with a first thickness and a second thickness is formed by initially implanting a portion of the gate area of the semiconductor substrate with nitrogen ions and then forming a gate oxide on the gate area. Preferably the gate oxide is grown by exposing the gate area to an environment of oxygen. A nitrogen implant inhibits the rate of SiO2 growth in an oxygen environment. Therefore, the portion of the gate area with implanted nitrogen atoms will grow or form a layer of gate oxide, such as SiO2, which is thinner than the portion of the gate area less heavily implanted or not implanted with nitrogen atoms. The gate oxide layer could be deposited rather than growing the gate oxide layer. After forming the gate oxide layer, polysilicon is deposited onto the gate oxide. The semiconductor substrate can then be implanted to form doped drain and source regions. Spacers can then be placed over the drain and source regions and adjacent the ends of the sidewalls of the gate.

Abstract: A diffusion-retarding barrier region is incorporated into the gate electrode to reduce the downward diffusion of dopant toward the gate dielectric. The barrier region is a nitrogen-containing diffusion retarding barrier region formed between two separately formed layers of polysilicon. The upper layer of polysilicon is doped more heavily than the lower layer of polysilicon, and the barrier region serves to keep most of the dopant within the upper layer of polysilicon, and yet may allow some of the dopant to diffuse into the lower layer of polysilicon. The barrier region may be formed, for example, by annealing the first polysilicon layer in an nitrogen-containing ambient to form a nitrided layer at the top surface of the first polysilicon layer. The barrier region may alternatively be formed by depositing a nitrogen-containing layer, such as a silicon nitride or titanium nitride layer, on the top surface of the first polysilicon layer.

Abstract: An IGFET with a silicide contact on an ultra-thin gate is disclosed. A method of forming the IGFET includes forming a gate over a semiconductor substrate, forming a source and a drain in the substrate, depositing a contact material over the gate, and reacting the contact material with the gate to form a silicide contact on the gate and consume at least one-half of the gate. By consuming such a large amount of the gate, a relatively thin gate can be converted into an ultra-thin gate with a thickness on the order of 100 to 200 angstroms. Preferably, the bottom surface of the gate is essentially undoped before reacting the contact material with the gate, and reacting the contact material with the gate pushes a peak concentration of a dopant in the gate towards the substrate so that a heavy concentration of the dopant is pushed to the bottom surface of the gate without being pushed into the substrate.

Abstract: A method for forming a multilevel interconnect structure having a globally planarized upper surface. Dielectrics are deposited upon a semiconductor to minimize pre-existing disparities in topographical height and to create an upper surface topography having a polish rate greater than that of lower regions. Subsequent chemical mechanical polishing produces a substantially planar surface.

Abstract: A method of forming a transistor includes forming a source/drain implant in the initial processing stages just after the formation of the isolation and active regions on the substrate. A uniform nitride layer is formed over the surface of the substrate on top of a dielectric layer. A silicide metal is then deposited and reacted with the underlying silicon to form a salicide over the source and drain regions. A second dielectric layer is then formed on top of the salicide and is formed to be selective relative to the nitride layer. Thereafter, the nitride layer is removed and a final gate dielectric is then formed. Finally, a metal gate conductor is formed on top of the gate dielectric. The metal gate conductor is formed only after all annealing steps are performed to prevent the metal from spiking through the gate dielectric thereby ruining the device.

Abstract: A method of making an IGFET using solid phase diffusion is disclosed. The method includes providing a device region in a semiconductor substrate, forming a gate insulator on the device region, forming a gate on the gate insulator, forming an insulating layer over the gate and the device region, forming a heavily doped diffusion source layer over the insulating layer, and driving a dopant from the diffusion source layer through the insulating layer into the gate and the device region by solid phase diffusion, thereby heavily doping the gate and forming a heavily doped source and drain in the device region. Preferably, the gate and diffusion source layer are polysilicon, the gate insulator and insulating layer are silicon dioxide, the dopant is boron or boron species, and the dopant provides essentially all P-type doping for the gate, source and drain, thereby providing shallow channel junctions and reducing or eliminating boron penetration from the gate into the substrate.

Abstract: A semiconductor fabrication process in which enhanced salicidation and reliability is achieved by implanting a silicon bearing species and a nitrogen bearing species into the source/drain regions and polysilicon regions of an integrated circuit transistor prior to the silicide formation sequence. A gate dielectric is formed on an upper surface of a semiconductor substrate. The substrate includes an active region that is laterally disposed between a pair of isolation structures. The active region includes a channel region that is laterally disposed between a pair of source/drain regions. A conductive gate structure is formed on the upper surface of the semiconductor substrate aligned over the channel region A silicon bearing species is then implanted or otherwise introduced into the conductive gate structure and into the source/drain regions to form amorphous silicon rich regions proximal to respective upper surfaces of the source/drain regions and the conductive gate structure.

Abstract: A transistor is provided and formed using self-aligned low-resistance source and drain regions within a metal-oxide semiconductor (MOS) process. The gate of the transistor may also be formed from a low-resistance material such as a metal. The transistor channel is located in a polysilicon layer arranged over a dielectric layer on a semiconductor substrate. To fabricate the transistor, an isolating dielectric, polysilicon layer, and protective dielectric layer are deposited over a semiconductor substrate. Source/drain trenches are formed in the protective dielectric and polysilicon layers and subsequently filled with sacrificial dielectrics. The protective dielectric lying between these sacrificial dielectrics is removed, and replaced with sidewall spacers, a gate dielectric, and a gate conductor which may be formed from a low-resistance metal. The sacrificial dielectrics are subsequently removed and replaced with source/drain regions which may be formed from a low-resistance metal.

Abstract: One method of making a semiconductor device includes forming a gate electrode on a substrate and forming a spacer on a sidewall of the gate electrode. An active region is then formed in the substrate and adjacent to the spacer, but spaced apart from the gate electrode, using a first dopant material. A halo region is formed in the substrate under the spacer and adjacent to the active region using a second dopant material of a conductivity type different than the first dopant material. The halo region may be formed by implanting the second dopant region into the substrate at an angle substantially less than 90° relative to a surface of the substrate. A portion of the spacer is then removed and a lightly-doped region is formed in the substrate adjacent to the active region and the gate electrode and shallower than the halo region using a third dopant material of a same conductivity type as the first dopant material.

Abstract: A transistor fabrication process is provided which derives a benefit from having barrier atoms incorporated in a lateral area under a gate oxide of the transistor in close proximity to the drain. To form the transistor, a gate oxide layer is first grown across a silicon-based substrate. A polysilicon layer is then deposited across the gate oxide layer. Portions of the polysilicon layer and the oxide layer are removed to form a gate conductor and gate oxide, thereby exposing source-side and drain-side junctions within the substrate. An LDD implant is performed to lightly dope the source-side and drain-side junctions. An etch stop material may be formed upon opposed sidewall surfaces of the gate conductor, the upper surface of the gate conductor, and the source-side and drain-side junctions. Spacers may then be formed laterally adjacent the etch stop material located upon sidewall surfaces of the gate conductor.

Abstract: An isolation technique is provided for improving the overall planarity of isolation regions relative to adjacent active area silicon mesas. The isolation process results in a trench formed in field regions immediately adjacent the active regions. The trench, however, does not extend entirely across the field region. By preventing large area trenches, substantial dielectric fill material and the problems of subsequent planarization of that fill material is avoided. Accordingly, the present isolation technique does not require conventional fill dielectric normally associated with a shallow trench process. While it achieves the advantages of forming silicon mesas, the present process avoids having to rework dielectric surfaces in large area field regions using conventional sacrificial etchback, block masking and chemical-mechanical polishing. The improved isolation technique hereof utilizes trenches of minimal width etched into the silicon substrate at the periphery of field regions, leaving a field mesa.

Abstract: A method for filling a trench is provided. A wafer having at least a first layer formed thereon is provided. A trench is formed in the first layer. The depth of the trench is measured. A target thickness is determined based on the depth of the trench. A second layer of the target thickness is formed over the trench. A processing line includes a trench etch tool, a first metrology tool, a trench fill tool, and an automatic process controller. The trench etch tool is adapted to form a trench in a first layer on a wafer. The first metrology tool is adapted to measure the depth of the trench. The trench fill tool is adapted to form a second layer over the first layer based on an operating recipe. An automatic process controller is adapted to determine a target thickness based on the depth of the trench and modify the operating recipe of the trench fill tool based on the target thickness.

Abstract: An integrated circuit fabrication process is provided for incorporating barrier atoms, preferably nitrogen atoms, within a barrier layer. The barrier layer is interposed between the gate dielectric and the semiconductor substrate. The barrier layer serves to inhibit the passage of dopants from the gate conductor into the channel area. The barrier layer is preferably a nitrogen doped silicon epitaxial layer. The barrier layer may be composed of two layers, a silicon epitaxial layer and a nitrogen doped epitaxial layer formed upon the silicon epitaxial layer.

Abstract: The present invention is directed to a method of forming conductive interconnections in an integrated circuit device to optimize or at least maintain the speed at which signals propagate throughout the integrated circuit device. In one embodiment, the method comprises determining any variation in the size of a contact, as compared to its design size, and varying the size of a conductive line to be coupled to the contact based upon the variation in the size of the contact.

Abstract: Methods of fabricating an isolation structure on a substrate are provided. In one aspect, a method of fabricating an isolation structure on a substrate is provided that includes forming a first insulating layer on the substrate wherein the first insulating layer has a first sidewall. A trench is formed in the substrate that has a second sidewall. A second insulating layer is formed in the trench. The second insulating layer displaces the second sidewall laterally. The first insulating layer is densified by heating to liberate gas therefrom and thereby move the first sidewall into substantial vertical alignment with the second sidewall. The risk of substrate attack due to trench isolation structure pullback is reduced. Trench edges are covered by thick isolation material.

Abstract: The present invention is directed to a method of forming a transistor having very shallow junctions and a reduced channel length, and a transistor incorporating same. In general, the method comprises forming a first process layer above a semiconducting substrate, and forming a second process layer comprised of an oxidation resistant material above the first process layer. The method continues with the formation of an opening in the first and second process layers and oxidation of the substrate lying within the opening to form a third process layer. Next, a second opening is formed in the third process layer, and a plurality of sidewall spacers are formed in the second opening. The method concludes with the formation of a gate dielectric above the substrate and between the sidewall spacers, the formation of a gate conductor above the gate dielectric, and the formation of a plurality of source and drain regions in the substrate.

Abstract: A transistor and a transistor fabrication method for forming an LDD structure in which the n-type dopants associated with an n-channel transistor are formed prior to the formation of the p-type dopants is presented. The n-type source/drain and LDD implants generally require higher activation energy (thermal anneal) than the p-type source/drain and LDD implants. The n-type arsenic source/drain implant, which has the lowest diffusivity and requires the highest temperature anneal, is performed first in the LDD process formation. Performing such a high temperature anneal first ensures minimum additional migration of subsequent, more mobile implants. Mobile implants associated with lighter and less dense implant species are prevalent in LDD areas near the channel perimeter. The likelihood of those implants moving into the channel is lessened by tailoring subsequent anneal steps to temperatures less than the source/drain anneal step.

Abstract: A transistor is provided with a graded source/drain junction. At least two dielectric spacers are formed in sequence upon the gate conductor. Adjacent dielectric spacers have dissimilar etch characteristics. An ion implant follows the formation of at least two of the dielectric spacers to introduce dopants into the source/drain region of the transistor. The ion implants are placed in different positions a spaced distance from the gate conductor according to a thickness of the dielectric spacers. As the implants are introduced further from the channel, the implant dosage and energy is increased. In a second embodiment, the ion implants are performed in reverse order. The dielectric spacers pre-exist on the sidewall surfaces of the gate conductor. The spacers are sequentially removed followed by an ion implant. An etchant is used which attacks the spacer to be removed but not the spacer beneath to the one being removed.

Abstract: A semiconductor integrated circuit having a multiple split gate is forming using a first polysilicon layer and a second polysilicon layer to form alternating first and second gate electrodes within an active area. The alternating gate electrodes are electrically isolated from one another by means of a gate insulating layer that is formed adjacent the side-walls of each firs gate electrode. Source and drain regions are formed adjacent the ends of the multiple split gate to define a channel region.