Psemi Corporation

Murata Manufacturing Co., Ltd.

Abhijeet Paul

Alain Duvallet

Hiroshi Yamada

Simon Edward Willard

Ronald Eugene Reedy

Richard James Dowling

A FET IC structure made using a back-side access process that mitigates or eliminates thermal conductivity problems. In some embodiments, electrically-isolated thermal paths are formed adjacent the FET and configured to conduct heat laterally away from the FET to generally orthogonal thermal pathways, and thence to thermal pads externally accessible at the 'top' of the completed IC. In some embodiments having a thermally-conductive handle wafer, electrically-isolated thermal paths are formed adjacent a FET and configured to conduct heat laterally away from the FET. Thermal vias are formed sufficiently so as to be in thermal contact with the handle wafer and with the conventional metallization layers of the device superstructure, at least one of which is in thermal contact with the lateral thermal paths. In some embodiments, the lateral thermal paths may use dummy gates configured to conduct heat laterally away from a FET to generally orthogonal thermal pathways.

Thermal extraction of single layer transfer integrated circuits

FET designs that exhibit low leakage in the presence of the edge transistor phenomenon. Embodiments includes nFET designs in which the work function Φof the gate structure overlying the edge transistors of the nFET is increased by forming extra P+ implant regions within at least a portion of the gate structure, thereby increasing the Vt of the edge transistors to a level that may exceed the Vt of the central conduction channel of the nFET. In some embodiments, the gate structure of the nFET is modified to increase or 'flare' the effective channel length of the edge transistors relative to the length of the central conduction channel of the FET. Other methods of changing the work function Φof the gate structure overlying the edge transistors are also disclosed. The methods may be adapted to fabricating pFETs by reversing or substituting material types.

Low leakage FET

FET IC structures that enable formation of integrated capacitors in a 'flipped' SOI IC structure made using a back-side access process, such as a “single layer transfer” (SLT) process, and which eliminate or mitigate unwanted parasitic couplings to a handle wafer. In some embodiments, a conductive interconnect layer may be patterned, pre-SLT, to form an isolated first capacitor plate. In other embodiments, pre-SLT, a conductive region of the active layer of an IC may be patterned to form an isolated first capacitor plate, with one or more interconnect layers being fabricated in position to form an electrical contact to the first capacitor plate. In either case, a post-SLT top-side layer of conductive material may be patterned to form a second capacitor plate. Couplings to the resulting capacitor structures include only external connections, only internal connections, or both internal and external connections

SLT integrated circuit capacitor structure and methods

A high-voltage switching device that can be fabricated in a standard low-voltage process, such as CMOS, and more specifically SOI CMOS. Embodiments include integrated circuits that combine, in a unitary structure, a FET device and an integrated, co-fabricated modulated resistance region (MRR) controlled by one or more Voltage-Drop Modulation Gates (VDMGs). The VDMGs are generally biased independently of the gate of the FET device, and in such a way as to protect each VDMG from excessive and potentially destructive voltages. In a first embodiment, an integrated circuit high voltage switching device includes a transistor structure including a source, a gate, and an internal drain; an MRR connected to the internal drain of the transistor structure; at least one VDMG that controls the resistance of the MRR; and a drain electrically connected to the MRR. Each VDMG at least partially depletes the MRR upon application of a bias voltage.

High voltage switching device

FET IC structures that enable formation of integrated capacitors in a 'flipped' SOI IC structure made using a back-side access process, such as a 'single layer transfer' (SLT) process, and which eliminate or mitigate unwanted parasitic couplings to a handle wafer. In some embodiments, a conductive interconnect layer may be patterned, pre-SLT, to form an isolated first capacitor plate. In other embodiments, pre-SLT, a conductive region of the active layer of an IC may be patterned to form an isolated first capacitor plate, with one or more interconnect layers being fabricated in position to form an electrical contact to the first capacitor plate. In either case, a post-SLT top-side layer of conductive material may be patterned to form a second capacitor plate. Couplings to the resulting capacitor structures include only external connections, only internal connections, or both internal and external connections.

FET designs that exhibit low leakage in the presence of the edge transistor phenomenon. Embodiments includes nFET designs in which the work function &#x3a6;of the gate structure overlying the edge transistors of the nFET is increased by forming extra P+ implant regions within at least a portion of the gate structure, thereby increasing the Vt of the edge transistors to a level that may exceed the Vt of the central conduction channel of the nFET. In some embodiments, the gate structure of the nFET is modified to increase or 'flare' the effective channel length of the edge transistors relative to the length of the central conduction channel of the FET. Other methods of changing the work function &#x3a6;of the gate structure overlying the edge transistors are also disclosed. The methods may be adapted to fabricating pFETs by reversing or substituting material types.

Structures and fabrication methods for transistors having low parasitic capacitance, the transistors including an insulating low dielectric constant first or second handle wafer. In one embodiment, a Single Layer Transfer technique is used to position an insulating LDC handle wafer proximate the metal interconnect layers of an SOI transistor/metal layer stack in lieu of the silicon substrate of conventional designs. In another embodiment, a Double Layer Transfer technique is used to replace the silicon substrate of prior art structures with an insulating LDC substrate. In some embodiments, the insulating LDC handle wafer includes at least one air cavity, which reduces the effective dielectric constant of material surrounding an RF FET. An insulating LDC handle wafer reduces insertion loss and non-linearity, increases isolation, provides for more ideal voltage division of stacked transistors, enables a higher Q factor due to lower coupling losses, and otherwise mitigates various parasitic effects.

Low parasitic capacitance RF transistors

High density integrated circuit (IC) capacitor structures and fabrication methods that increase the capacitive density of integrated capacitors with little or no reduction in Q-factor by using a stacked high-density integrated capacitor structure that includes substrate-contact ('S-contact') capacitor plates. Embodiments include a plurality of S-contact plates fabricated in electrical connection with a capacitor formed in a metal interconnect layer. Some embodiments include interstitial S-contact plates to provide additional capacitive density. Embodiments may also utilize single-layer transfer (SLT) and double-layer transfer (DLT) techniques to create ICs with high density, high Q-factor capacitors. Such capacitors can be beneficially combined with other structures made possible in SLT and DLT IC structures, such as metal interconnect layer capacitors and inductors, and one or more FETs having a conductive aligned supplemental gate. Embodiments are compatible with fabrication of CMOS SOI transistors, and are particularly suitable for radio frequency and analog applications.

High density IC capacitor structure

FET IC structures that enable formation of high-Q inductors in a 'flipped' SOI IC structure made using a back-side access process, such as an single layer transfer (SLT) process. Essentially, the interconnect layer superstructure of an IC is split into two parts, a 'lower' superstructure and an &#x201c;upper&#x201d; superstructure. In various embodiments, one or more low-resistance interconnect layers are fabricated within an upper superstructure formed after the application of a back-side access process, allowing fabrication of inductors in one or more low-resistance interconnect layer. A significant advantage of such IC structures is that the low-resistance interconnect layer or layers are relocated from being near the handle wafer of a conventional SLT IC to being spaced away from the handle wafer by intervening structures. Fabricating inductors in such spaced low-resistance interconnect layer or layers reduces electromagnetic coupling with the handle wafer and thus increases the Q factor of the inductors.

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Poway, CA, United States of America

Abhijeet Paul