Abstract:
A method of fabricating an integrated circuit with ultra-shallow source/drain junctions utilizes a dual amorphization technique. The technique creates a shallow amorphous region and a deep amorphous region. The shallow amorphous region is between 10-15 nm below the top surface of the substrate, and the deep amorphous region is between 150-200 nm below the top surface of the substrate. The process can be utilized for P-channel or N-channel metal oxide semiconductor field effect transistors (MOSFETs). In the case of a P-channel MOSFET, a nitrogen barrier is formed in the P-channel gate prior to p+ doping. Annealing the gate conductor is done in a step separate from the source/drain region annealing step.
Abstract:
An integrated circuit includes multiple active layers. Preferably, a semiconductor-on-insulator (SOI) or silicon-on-insulator wafer is utilized to house a first active layer. A second active layer is provided by bonding a bulk substrate to the SOI substrate and removing the bulk substrate to leave a thin semiconductor layer. Subsequent active layers can be added by a similar technique. Preferably, the bulk substrates utilize a hydrogen implant to provide a breaking interface.
Abstract:
A method for reducing lateral dopant gradient diffusion in the source/drain extension (SDE) region of a MOSFET includes forming the deep source and drain using high temperature dopant activation annealing, and then implanting a preamorphization species in an amorphized extension region that is to become the SDE region. Then, both SDE dopant and, if desired, halo dopant are implanted into the amorphized extension region and activated using relatively low temperature annealing, thereby reducing the thermal budget of the process and concomitantly reducing unwanted dopant thermal diffusion.
Abstract:
For fabricating a field effect transistor, a gate structure is formed on a gate dielectric on an active device area of a semiconductor substrate. A liner layer of a non-dielectric material is formed on sidewalls of the gate dielectric, and on a drain extension area and a source extension area of the active device area of the semiconductor substrate. First spacers of dielectric material are formed on the liner layer at sidewalls of the gate structure and over the drain and source extension areas. A contact junction dopant is implanted into exposed regions of the active device area of the semiconductor substrate to form a drain contact junction and a source contact junction. The first spacers of dielectric material are etched using a first type of etching reactant that etches the first spacers but not the liner layer such that the gate dielectric is not exposed to the first type of etching reactant. The liner layer of the non-dielectric material is etched using a second type of etching reactant that etches the liner layer but not the gate structure and the gate dielectric. A first thermal anneal is performed to activate the contact junction dopant within the drain and source contact junctions. After this first thermal anneal, a drain extension junction is formed in the drain extension area and a source extension junction is formed in the source extension area by implantation of an extension junction dopant. In this manner, the drain and source extension junctions are not heated up during the first thermal anneal for activating the contact junction dopant. Thus, transient enhanced diffusion of the extension junction dopant is minimized to maintain the shallow depth of the drain and source extension junctions such that short-channel effects are minimized for the field effect transistor having scaled down dimensions.
Abstract:
A method of providing a field effect transistor includes depositing a layer of a laser-reflective material on a substrate which has an active region and an inactive region; selectively removing portions of the deposited layer disposed over the active region; exposing laser energy to activate dopants in the active region; and stripping the deposited layer.
Abstract:
Drain and source extensions that are abrupt and shallow and that have high concentration of dopant are fabricated for a field effect transistor, using a laser thermal process. A drain amorphous region is formed by implanting a neutral species into a drain region of the field effect transistor at an angle directed toward a gate of the field effect transistor such that the drain amorphous region is a trapezoidal shape that extends to be sufficiently under the gate of the field effect transistor. A source amorphous region is formed by implanting the neutral species into a source region of the field effect transistor at an angle directed toward the gate of the field effect transistor such that the source amorphous region is a trapezoidal shape that extends to be sufficiently under the gate of the field effect transistor. A drain and source dopant is implanted into the drain and source amorphous regions at an angle directed toward the gate of the field effect transistor. A laser beam is then applied to the drain and source amorphous regions such that the drain and source dopant is activated within the drain and source amorphous regions in a laser thermal process. The drain and source extensions are formed by the activation of the drain and source dopant in the drain and source amorphous regions respectively during the laser thermal process. The trapezoidal shape of the drain and source extensions minimizes the series resistance and the leakage current in the field effect transistor having scaled down dimensions.
Abstract:
An integrated circuit is provided having an improved packing density due to an improved isolation structure between a plurality of devices on the substrate. An ultra shallow trench isolation structure is provided, typically having a trench depth just deeper than the doped regions of a transistor or other device placed thereon, but substantially shallower than the depth of a well associated with the transistor. A nitrogen ion implantation step is utilized to fabricate an implanted portion beneath the insulative portion, the implanted portion extending preferably below the depth of the well. Due to a shallower trench isolation structure, the structure may also be narrower, providing for improved packing density in a semiconductor device.
Abstract:
A method of fabricating an integrated circuit with locally confined deep pocket regions utilizes a dummy or sacrificial gate spacer. Dopants are provided through the openings associated with sacrificial spacers to form the pocket regions. The dopants are provided after silicidation. The openings can be filled with spacers. The process can be utilized for P-channel or N-channel metal oxide field semiconductor effect transistors (MOSFETS).
Abstract:
An ultra-large-scale integrated (ULSI) circuit includes MOSFETs on a substrate. The MOSFETs include elevated source and drain regions. The elevated source and drain regions are adjacent ultra-shallow source and drain regions. Dopants in the ultra-shallow source and drain regions are activated in a low-temperature rapid thermal anneal process.
Abstract:
For fabricating a metal oxide structure on a semiconductor substrate, an active device area surrounded by at least one STI (shallow trench isolation) structure is formed in the semiconductor substrate. A layer of metal is deposited on the semiconductor substrate, and the layer of metal contacts the active device area of the semiconductor substrate. A layer of oxygen blocking material is deposited on the layer of metal. An opening is etched through the layer of oxygen blocking material to expose an area of the layer of metal on top of the active device area. A thermal oxidation process is performed to form a metal oxide structure from reaction of oxygen with the area of the layer of metal that is exposed. A thickness of the metal oxide structure is determined by a thickness of the layer of metal, and the layer of oxygen blocking material prevents contact of oxygen with the layer of metal such that the metal oxide structure is formed localized at the area where the layer of metal is exposed. In this manner, the metal oxide structure is formed by localized thermal oxidation of the layer of metal such that a deposition or sputtering process or an etching process is not necessary for formation of the metal oxide structure. In addition, the thickness of the metal oxide structure is determined by controlling the thickness of the layer of metal used for forming the metal oxide structure. Furthermore, these steps may be repeated for another layer of metal having a different thickness for forming a plurality of metal oxide structures having different thicknesses to provide gate dielectrics of MOSFETs (metal oxide semiconductor field effect transistors) having different threshold voltages on the same semiconductor substrate.