A method and apparatus are disclosed for use in improving the gate oxide reliability of semiconductor-on-insulator (SOI) metal-oxide-silicon field effect transistor (MOSFET) devices using accumulated charge control (ACC) techniques. The method and apparatus are adapted to remove, reduce, or otherwise control accumulated charge in SOI MOSFETs, thereby yielding improvements in FET performance characteristics. In one embodiment, a circuit comprises a MOSFET, operating in an accumulated charge regime, and means for controlling the accumulated charge, operatively coupled to the SOI MOSFET. A first determination is made of the effects of an uncontrolled accumulated charge on time dependent dielectric breakdown (TDDB) of the gate oxide of the SOI MOSFET. A second determination is made of the effects of a controlled accumulated charge on TDDB of the gate oxide of the SOI MOSFET. The SOI MOSFET is adapted to have a selected average time-to-breakdown, responsive to the first and second determinations, and the circuit is operated using techniques for accumulated charge control operatively coupled to the SOI MOSFET. In one embodiment, the accumulated charge control techniques include using an accumulated charge sink operatively coupled to the SOI MOSFET body.

Devices and methods for forming a device are disclosed. The method includes providing a crystalline-on-insulator substrate having a bulk substrate and a surface substrate separated by a buried insulator layer. The surface substrate is defined with a device region. A transistor having a gate is formed in the device region. A first diffusion region is formed adjacent to a first side of the gate and a second diffusion region is formed adjacent to and displaced away from a second side of the gate. At least a first drift isolation region is formed in the surface substrate adjacent to and underlaps the second side of the gate. A drift well is formed in the surface substrate encompassing the first drift isolation region. A device isolation region surrounding the device region is formed in the surface substrate. The device isolation region includes a second depth which is deeper than a first depth of the first drift isolation region.

Silicon-on-insulator integrated circuits including body contact structures and methods for fabricating the same are disclosed. A method for fabricating a silicon-on-insulator integrated circuit includes filling a plurality of first and second shallow isolation trenches with an insulating material to form plurality of first and second shallow trench isolation (STI) structures, the plurality of second shallow isolation trenches having doped regions therebeneath, and forming a gate structure over the semiconductor layer that includes a first portion disposed over and parallel to at least two of the plurality of second STI structures and a second portion disposed in between the at least two of the plurality of second STI structures. The method further includes forming contact plugs to a body contact or gate region of the semiconductor layer. The body contact region includes a portion of the semiconductor layer between at least one of the plurality of first STI structures and at least one of the plurality of second STI structures.

A novel semiconductor transistor is presented. The semiconductor structure has a MOSFET like structure, with the difference that the device channel is formed in an intrinsic region, so as to effectively decrease the impurity and surface scattering phenomena deriving from a high doping profile typical of conventional MOS devices. Due to the presence of the un-doped channel region, the proposed structure greatly reduces Random Doping Fluctuation (RDF) phenomena decreasing the threshold voltage variation between different devices. In order to control the threshold voltage of the device, a heavily doped poly-silicon or metallic gate is used. However, differently from standard CMOS devices, a high work-function metallic material, or a heavily p-doped poly-silicon layer, is used for an n-channel device and a low work-function metallic material, or heavily n-doped poly-silicon layer, is used for a p-channel FET. Doped or insulating regions are used to increase the control on the channel conductivity.

A method and apparatus for use in improving linearity sensitivity of MOSFET devices having an accumulated charge sink (ACS) are disclosed. The method and apparatus are adapted to address degradation in second- and third-order intermodulation harmonic distortion at a desired range of operating voltage in devices employing an accumulated charge sink.

A metal oxide semiconductor field effect transistor preferably fabricated with a silicon-on-insulator process has a first semiconductor region and a second semiconductor region in a spaced relationship thereto A body structure is defined by a channel segment between the first semiconductor region and the second semiconductor region, and a first extension segment structurally contiguous with the channel segment. A shallow trench isolation structure surrounds the first semiconductor region, the second semiconductor region, and the body structure, with a first extension interface being defined between the shallow trench isolation structure and the first extension segment of the body structure to reduce leakage current flowing from the second semiconductor region to the first semiconductor region through a parasitic path of the body structure.

Integrated circuit structures that significantly reduce the resistance associated with the body contact region and substrate region contact of a field-effect transistor (FET) compared to conventional designs. Embodiments include a FET having a body contact region, and optionally a substrate region contact, that includes germanium (Ge) alone or as an alloy with silicon (SiGe) and/or as a layered combination with silicon (e.g., a layer of Ge on a layer of Si). A first method includes fabricating a body contact region of a field-effect transistor by fabricating the field-effect transistor with an Si body contact region, and diffusing or implanting Ge within the Si. A second method includes fabricating a body contact region of a field-effect transistor by fabricating the field-effect transistor with an Si body contact region, etching away at least part of the Si body contact region to form a well, and depositing Ge within the well.

Systems, methods, and apparatus for an improved body tie construction that produces all the benefits of conventional body tie (H-gate, T-gate), without the limitations and degradations associated with those constructions are described. The improved body tie construction is configured to have a lower resistance body tie when the transistor is off (Vg approximately 0 volts). When the transistor is on (Vg>Vt), the resistance to the body tie is much higher, reducing the loss of performance associated with presence of body tie.

Systems, methods, and apparatus for an improved body tie construction are described. The improved body tie construction is configured to have a lower resistance body tie exists when the transistor is off (Vg approximately 0 volts). When the transistor is on (Vg>Vt), the resistance to the body tie is much higher, reducing the loss of performance associated with presence of body tie. Space efficient Body tie constructions adapted for cascode configurations are also described.

A method of forming a substrate contact in a vertical transistor device includes patterning a sacrificial layer to form an opening in the sacrificial layer, the sacrificial layer disposed on hardmask arranged on a substrate, and the substrate including a bulk semiconductor layer, a buried oxide layer arranged on the bulk semiconductor layer, and a semiconductor layer arranged on the buried oxide layer; forming oxide spacers on sidewalls of the opening in the sacrificial layer; using the oxide spacers as a pattern to etch a trench through the substrate, the trench stopping at a region within the bulk semiconductor layer; and depositing a conductive material in the trench to form the substrate contact.