Semiconductors & ICs

Making Wide-IF SIS Mixers With Suspended Metal-Beam Leads

Devices are fabricated on SOI substrates by use of silicon-micromachining techniques.

A process that employs silicon-on-insulator (SOI) substrates and silicon (Si) micromachining has been devised for fabricating wide intermediate frequency band (wide-IF) superconductor/ insulator/ superconductor (SIS) mixer devices that result in suspended gold beam leads used for radio-frequency grounding. The mixers are formed on 25-µm-thick silicon membranes. They are designed to operate in the 200 to 300 GHz frequency band, wherein wide-IF receivers for tropospheric- chemistry and astrophysical investigations are necessary. The fabrication process can be divided into three sections:

Posted in: Briefs, TSP, Semiconductors & ICs, Fabrication, Forming, Semiconductors
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Mathematical Modeling of a Copper-Deposition System for Integrated Circuits

A unique process for making flip-chip IC receptacles required optimization through modeling.

Advanced packaging techniques are the key to utilizing state-of-the-art microelectronic devices. The flip-chip method has become a cost-effective means of erasing many packaging and thermal issues that could spell disaster for high-density, high-power integrated circuits (ICs). Making flip-chip receptacles presents significant engineering challenges. To overcome those challenges, Replisaurus developed a unique process that required mathematical modeling to better understand and optimize the patented process.

Posted in: Briefs, Semiconductors & ICs, Mathematical models, Integrated circuits, Integrated circuits, Packaging, Copper
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Stripline/Microstrip Transition in Multilayer Circuit Board

Transitions like this one could be useful in microwave communication products.

A stripline to microstrip transition has been incorporated into a multilayer circuit board that supports a distributed solid-state microwave power amplifier, for the purpose of coupling the microwave signal from a buried-layer stripline to a top-layer microstrip. The design of the transition could be adapted to multilayer circuit boards in such products as cellular telephones (for connecting between circuit-board signal lines and antennas), transmitters for Earth/satellite communication systems, and computer mother boards (if processor speeds increase into the range of tens of gigahertz).

Posted in: Briefs, TSP, Semiconductors & ICs, Amplifiers, Architecture, Integrated circuits, Amplifiers, Architecture, Integrated circuits, Semiconductors
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Multifunctional Logic Gate Controlled by Supply Voltage

This circuit performs different logic functions at different levels of supply voltage.

The figure is a schematic diagram of a complementary metal oxide/semiconductor (CMOS) electronic circuit that functions as a NAND gate at a power-supply potential (Vdd) of 3.3 V and as NOR gate for Vdd = 1.8 V. In the intermediate Vdd range of 1.8 to 3.3 V, this circuit performs a function intermediate between NAND and NOR with degraded noise margin. Like the circuit of the immediately preceding article, this circuit serves as a demonstration of the evolutionary approach to design of polymorphic electronics — a technological discipline that emphasizes evolution of the design of a circuit to perform different analog and/or digital functions under different conditions. In this instance, the different conditions are different values of Vdd.

Posted in: Briefs, TSP, Semiconductors & ICs, Adaptive control, Integrated circuits, Switches, Adaptive control, Integrated circuits, Switches, Semiconductors
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Multifunctional Logic Gate Controlled by Temperature

This circuit performs different logic functions at different temperatures.

The figure is a schematic diagram of a complementary metal oxide/semiconductor (CMOS) electronic circuit that has been designed to function as a NAND gate at a temperature between 0 and 80 °C and as a NOR gate at temperatures from 120 to 200 °C. In the intermediate temperature range of 80 to 120 °C, this circuit is expected to perform a function intermediate between NAND and NOR with degraded noise margin. The process of designing the circuit and the planned fabrication and testing of the circuit are parts of demonstration of polymorphic electronics — a technological discipline that emphasizes designing the same circuit to perform different analog and/or digital functions under different conditions. In this case, the different conditions are different temperatures.

Posted in: Briefs, TSP, Semiconductors & ICs, Adaptive control, Integrated circuits, Switches, Adaptive control, Integrated circuits, Switches, Thermodynamics, Thermodynamics, Semiconductors
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Improved Method of Manufacturing SiC Devices

Several improvements promise to make manufacture of SiC devices more economical.

The phrase, “common-layered architecture for semiconductor silicon carbide” (“CLASSiC”) denotes a method of batch fabrication of microelectromechanical and semiconductor devices from bulk silicon carbide. CLASSiC is the latest in a series of related methods developed in recent years in continuing efforts to standardize SiC-fabrication processes. CLASSiC encompasses both institutional and technological innovations that can be exploited separately or in combination to make the manufacture of SiC devices more economical. Examples of such devices are piezoresistive pressure sensors, strain gauges, vibration sensors, and turbulence-intensity sensors for use in harsh environments (e.g., high-temperature, high-pressure, corrosive atmospheres).

Posted in: Briefs, Semiconductors & ICs, Architecture, Semiconductor devices, Sensors and actuators, Architecture, Semiconductor devices, Sensors and actuators, Fabrication
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LC Circuits for Diagnosing Embedded Piezoelectric Devices

Failures are readily identified through changes in resonance frequencies.

A recently invented method of nonintrusively detecting faults in piezoelectric devices involves measurement of the resonance frequencies of inductor-capacitor (LC) resonant circuits. The method is intended especially to enable diagnosis of piezoelectric sensors, actuators, and sensor/actuators that are embedded in structures and/or are components of multilayer composite-material structures.

Posted in: Briefs, TSP, Semiconductors & ICs, Semiconductor devices, Sensors and actuators, Semiconductor devices, Sensors and actuators, Test procedures
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HEMT Frequency Doubler With Output at 300 GHz

This is the highest-frequency HEMT doubler reported to date.

An active frequency doubler in the form of an InP-based monolithic microwave integrated circuit (MMIC) containing a high electron mobility transistor (HEMT) has been demonstrated in operation at output frequencies in the vicinity of 300 GHz. This is the highest frequency HEMT doubler reported to date, the next highest frequency active HEMT doubler having been previously reported to operate at 180 GHz. While the output power of this frequency doubler is less than that of a typical Schottky diode, this frequency doubler is considered an intermediate product of a continuing effort to realize the potential of active HEMT frequency doublers to operate with conversion efficiencies greater than those of passive diode frequency doublers. An additional incentive for developing active HEMT frequency doublers lies in the fact that they can be integrated with amplifiers, oscillators, and other circuitry on MMIC chips.

Posted in: Briefs, TSP, Semiconductors & ICs, Integrated circuits, Waveguides, Integrated circuits, Waveguides, Semiconductors
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Single-Chip FPGA Azimuth Pre-Filter for SAR

Range resolution is reduced by a selectable factor to reduce the volume of data.

A field-programmable gate array (FPGA) on a single lightweight, low power integrated-circuit chip has been developed to implement an azimuth pre-filter (AzPF) for a synthetic-aperture radar (SAR) system. The AzPF is needed to enable more efficient use of data-transmission and data-processing resources: In broad terms, the AzPF reduces the volume of SAR data by effectively reducing the azimuth resolution, without loss of range resolution, during times when end users are willing to accept lower azimuth resolution as the price of rapid access to SAR imagery. The data-reduction factor is selectable at a decimation factor, M, of 2, 4, 8, 16, or 32 so that users can trade resolution against processing and transmission delays.

Posted in: Briefs, TSP, Semiconductors & ICs, Integrated circuits, Radar, Integrated circuits, Radar, Semiconductors
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Alumina or Semiconductor Ribbon Waveguides at 30 to 1,000 GHz

The waveguides would be configured to exploit low-loss electromagnetic modes.

Ribbon waveguides made of alumina or of semiconductors (Si, InP, or GaAs) have been proposed as low-loss transmission lines for coupling electronic components and circuits that operate at frequencies from 30 to 1,000 GHz. In addition to low losses (and a concomitant ability to withstand power levels higher than would otherwise be possible), the proposed ribbon waveguides would offer the advantage of compatibility with the materials and structures now commonly incorporated into integrated circuits.

Posted in: Briefs, TSP, Semiconductors & ICs, Waveguides, Waveguides, Materials properties, Semiconductors
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