Abstract: In fabricating a radio frequency (RF) switch, a phase-change material (PCM) and a heating element underlying an active segment of the PCM are provided. A contact uniformity support layer is formed over the PCM. The PCM and the contact uniformity support layer are patterned. A contact dielectric is formed over the contact uniformity support layer. Slot lower portions of PCM contacts are formed extending through the contact dielectric and through the contact uniformity support layer, and connected to passive segments of the PCM. Wide upper portions of the PCM contacts are formed over the contact dielectric and over the slot lower portions of the PCM contacts. The contact dielectric separates the wide upper portions of the PCM contacts from the heating element so as to reduce parasitic capacitance of the RF switch. The contact uniformity support layer maintains a substantially constant thickness of the passive segments of the PCM.

Abstract: A radio frequency (RF) device includes a phase-change material (PCM) situated over a sheet of thermally conductive and electrically insulating material, a heating element situated under the sheet of thermally conductive and electrically insulating material, and an input/output terminal situated over the PCM. The heating element is situated in a dielectric. A heat spreader is situated under the dielectric and over a substrate. Metal interconnect layers can be situated under and/or over the PCM, with the substrate situated below the metal interconnect layers.

Abstract: A silicon-on-insulator (SOI) CMOS transistor and a SOI heterojunction bipolar transistor (HBT) are fabricated on the same semiconductor substrate. First and second SOI regions are formed over the semiconductor substrate. A SOI CMOS transistor is fabricated in the first SOI region, and a collector region of the SOI HBT is fabricated in the second SOI region. The collector region can be formed by performing a first implant to a local collector region in the second SOI region, and performing a second implant to an extrinsic collector region in the second SOI region, wherein the extrinsic collector region is separated from the local collector region. A SiGe base is formed over the collector region, wherein a dielectric structure separates portions of the SiGe region and the extrinsic collector region. The SOI CMOS transistor and SOI HBT may be used to implement a front end module of an RF system.

Abstract: A semiconductor structure includes a porous semiconductor segment adjacent to a first region of a substrate, and a crystalline epitaxial layer situated over the porous semiconductor segment and over the first region of the substrate. A first semiconductor device is situated in the crystalline epitaxial layer over the porous semiconductor segment. The first region of the substrate has a first dielectric constant, and the porous semiconductor segment has a second dielectric constant that is substantially less than the first dielectric constant such that the porous semiconductor segment reduces signal leakage from the first semiconductor device. The semiconductor structure can include a second semiconductor device situated in the crystalline epitaxial layer over the first region of the substrate, and an electrical isolation region separating the first and second semiconductor devices.

Abstract: A semiconductor structure includes a substrate having a first dielectric constant, a porous semiconductor layer situated over the substrate, and a crystalline epitaxial layer situated over the porous semiconductor layer. A first semiconductor device is situated in the crystalline epitaxial layer. The porous semiconductor layer has a second dielectric constant that is substantially less than the first dielectric constant such that the porous semiconductor layer reduces signal leakage from the first semiconductor device. The semiconductor structure can include a second semiconductor device situated in the crystalline epitaxial layer, and an electrical isolation region separating the first and second semiconductor devices.

Abstract: A semiconductor structure includes a semiconductor substrate, a porous semiconductor region within the semiconductor substrate, and through-substrate via (TSV) within the porous semiconductor region. The porous semiconductor region causes the semiconductor structure and/or the TSV to withstand thermal and mechanical stresses. Alternatively, the semiconductor structure includes a semiconductor buffer ring within the porous semiconductor region, and the TSV within the semiconductor buffer ring.

Abstract: A circuit according to the present application includes a diode or other non-linear device coupled to a heating element of a phase-change material (PCM) radio frequency (RF) switch. The diode or other non-linear device allows an amorphizing pulse or a crystallizing pulse to pass to a first terminal of the heating element. The diode or other non-linear device substantially prevents a pulse generator providing the amorphizing pulse or crystallizing pulse from interfering with RF signals at RF terminals of the PCM RF switch. In an array of PCM cells each including a diode or other non-linear device, the diode or other non-linear device substantially prevents sneak paths that would otherwise enable an amorphizing or crystallizing pulse intended for a heating element of a selected cell of the array to be provided to heating elements of unselected cells of the array.

Abstract: A radio frequency (RF) switch includes a heating element, an aluminum nitride layer situated over the heating element, and a phase-change material (PCM) situated over the aluminum nitride layer. An inside segment of the heating element underlies an active segment of the PCM, and an intermediate segment of the heating element is situated between a terminal segment of the heating element and the inside segment of the heating element. The aluminum nitride layer situated over the inside segment of the heating element provides thermal conductivity and electrical insulation between the heating element and the active segment of the PCM. The aluminum nitride layer extends into the intermediate segment of the heating element and provides chemical protection to the intermediate segment of the heating element, such that the intermediate segment of the heating element remains substantially unetched and with substantially same thickness as the inside segment.

Abstract: A radio frequency (RF) switch includes a phase-change material (PCM), a heating element underlying an active segment of the PCM and extending outward and transverse to the PCM, a capacitive RF terminal, and an ohmic RF terminal. The capacitive RF terminal can include a first trench metal liner situated on a first passive segment of the PCM, and a dielectric liner separating the first trench metal liner from a first trench metal plug. The ohmic RF terminal can include a second trench metal liner situated on a second passive segment of the PCM, and a second trench metal plug ohmically connected to the second trench metal liner. Alternatively, the capacitive RF terminal and the ohmic RF terminal can include lower metal portions and upper metal portions. A MIM capacitor can be formed by the upper metal portion of the capacitive RF terminal, an insulator, and a patterned top plate.

Abstract: There are disclosed herein various implementations of a semiconductor device including a group III-V layer situated over a substrate, and a phase-change material (PCM) radio frequency (RF) switch situated over the group III-V layer. The PCM RF switch couples a group III-V transistor situated over the group III-V layer to one of an integrated passive element or another group III-V transistor situated over the group III-V layer. The PCM RF switch includes a heating element transverse to the PCM, the heating element underlying an active segment of the PCM. The PCM RF switch is configured to be electrically conductive when the active segment of the PCM is in a crystalline state, and to be electrically insulative when the active segment of the PCM is in an amorphous state.

Abstract: A radio frequency (RF) switching circuit includes stacked phase-change material (PCM) RF switches. The stacked PCM RF switches can include a high shunt capacitance PCM RF switch having its heating element contacts near its PCM contacts, and a low shunt capacitance PCM RF switch having its heating element contacts far from its PCM contacts. An RF voltage is substantially uniformly distributed between the high shunt capacitance PCM RF switch and the low shunt capacitance PCM RF switch. The stacked PCM RF switches can also include a wide heating element PCM RF switch having a large PCM active segment, and a narrow heating element PCM RF switch having a small PCM active segment. The wide heating element PCM RF switch will have a higher breakdown voltage than the narrow heating element PCM RF switch.

Abstract: In manufacturing a radio frequency (RF) switch, a heat spreader is provided. A first dielectric is deposited over the heat spreader. A trench is etched in the first dielectric. A heating element is deposited in the trench and over at least a portion of the first dielectric. A thermally conductive and electrically insulating material is deposited over at least the heating element, where the thermally conductive and electrically insulating material is self-aligned with the heating element. A conformability support layer is optionally deposited over the thermally conductive and electrically insulating material and the first dielectric. A phase-change material is deposited over the optional conformability support layer and the underlying thermally conductive and electrically insulating material and the first dielectric.

Abstract: A radio frequency (RF) switch includes a phase-change material (PCM), a heating element underlying an active segment of the PCM and extending outward and transverse to the PCM, and RF terminals having lower metal portions and upper metal portions. At least one of the lower metal portions can be ohmically separated from and capacitively coupled to passive segments of the PCM, while the upper metal portions are ohmically connected to the lower metal portions. Alternatively, the lower metal portions can be ohmically connected to passive segments of the PCM, while a capacitor is formed in part by at least one of the upper metal portions. Alternatively, at least one of the RF terminals can have a trench metal liner separated from a trench metal plug by a dielectric liner. The trench metal liner can be ohmically connected to passive segments of the PCM, while the trench metal plug is ohmically separated from, but capacitively coupled to, the trench metal liner.

Abstract: A rapid testing read out integrated circuit (ROIC) includes phase-change material (PCM) radio frequency (RF) switches residing on an application specific integrated circuit (ASIC). Each PCM RF switch includes a PCM and a heating element transverse to the PCM. The ASIC is configured to provide amorphizing and crystallizing electrical pulses to a selected PCM RF switch. The ASIC is also configured to determine if the selected PCM RF switch is in an OFF state or in an ON state. In one implementation, a testing method using the ASIC is disclosed.

Abstract: A radio frequency (RF) switch includes a heating element, thermally conductive and electrically insulating layer over the heating element, a wetting dielectric layer over the thermally conductive and electrically insulating layer, and a phase-change material (PCM) over the wetting dielectric layer. At least one cladding dielectric layer can be situated over sides and/or over a top surface of the PCM. Each of the wetting dielectric layer, phase change material, and cladding dielectric layer can comprise at least germanium. A transitional dielectric layer can be situated between the thermally conductive and electrically insulating layer and the wetting dielectric layer. A contact uniformity support layer can be situated over the cladding dielectric layer.

Abstract: In fabricating a radio frequency (RF) switch, a heat spreader is provided and a heating element is deposited. A thermally conductive and electrically insulating material is deposited over the heating element. The heating element and the thermally conductive and electrically insulating material are patterned, where the thermally conductive and electrically insulating material is self-aligned with the heating element. A layer of an upper dielectric is deposited. A conformability support layer is optionally deposited over the upper dielectric and the thermally conductive and electrically insulating material. A phase-change material is deposited over the optional conformability support layer and the underlying upper dielectric and the thermally conductive and electrically insulating material.

Abstract: A radio frequency (RF) switch includes a phase-change material (PCM), a heating element underlying an active segment of the PCM and extending outward and transverse to the PCM, and RF terminals having lower metal portions and upper metal portions. At least one of the lower metal portions can be ohmically separated from and capacitively coupled to passive segments of the PCM, while the upper metal portions are ohmically connected to the lower metal portions. Alternatively, the lower metal portions can be ohmically connected to passive segments of the PCM, while a capacitor is formed in part by at least one of the upper metal portions. Alternatively, at least one of the RF terminals can have a trench metal liner separated from a trench metal plug by a dielectric liner. The trench metal liner can be ohmically connected to passive segments of the PCM, while the trench metal plug is ohmically separated from, but capacitively coupled to, the trench metal liner.

Abstract: In fabricating a radio frequency (RF) switch, a phase-change material (PCM) and a heating element, underlying an active segment of the PCM and extending outward and transverse to the PCM, are provided. Lower portions of PCM contacts for connection to passive segments of the PCM are formed, wherein the passive segments extend outward and are transverse to the heating element. Upper portions of the PCM contacts are formed from a lower interconnect metal. Heating element contacts are formed cross-wise to the PCM contacts. The heating element contacts can comprise a top interconnect metal directly connecting with terminal segments of the heating element. The heating element contacts can comprise a top interconnect metal and intermediate metal segments for connecting with the terminal segments of the heating element.

Abstract: A capacitive tuning circuit includes radio frequency (RF) switches connected to an RF line. Each RF switch includes a phase-change material (PCM), a heating element underlying an active segment of the PCM and extending outward and transverse to the PCM, and RF terminals having lower metal portions and upper metal portions. Alternatively, the RF terminals can have a trench metal liner separated from a trench metal plug by a dielectric liner. At least one capacitor is formed in part by at least one of the lower metal portions, upper metal portions, or trench metal liner. The capacitive tuning circuit can be set to a desired capacitance value when a first group of the RF switches is in an OFF state and a second group of the RF switches is in an ON state.

Abstract: A radio frequency (RF) switch includes a heating element, an aluminum nitride layer situated over the heating element, and a phase-change material (PCM) situated over the aluminum nitride layer. An inside segment of the heating element underlies an active segment of the PCM, and an intermediate segment of the heating element is situated between a terminal segment of the heating element and the inside segment of the heating element. The aluminum nitride layer situated over the inside segment of the heating element provides thermal conductivity and electrical insulation between the heating element and the active segment of the PCM. The aluminum, nitride layer extends into the intermediate segment of the heating element and provides chemical protection to the intermediate segment of the heating element, such that the intermediate segment of the heating element remains substantially unetched and with substantially same thickness as the inside segment.