Semiconductors & ICs

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: Semiconductors & ICs, Briefs, TSP

Read More >>

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: Semiconductors & ICs, Briefs, TSP

Read More >>

Apparatus for Precise Indium-Bump Bonding of Microchips

Bonding force is distributed more nearly evenly and controlled more precisely. An improved apparatus has been designed and built for use in precise positioning and pressing of a microchip onto a substrate (which could, optionally, be another microchip) for the purpose of indium-bump bonding. The apparatus (see figure) includes the following:  

Posted in: Semiconductors & ICs, Briefs, TSP

Read More >>

Multiple Embedded Processors for Fault-Tolerant Computing

Outputs of processors would be compared to detect and correct bit errors.A fault-tolerant computer architecture has been conceived in an effort to reduce vulnerability to single-event upsets (spurious bit flips caused by impingement of energetic ionizing particles or photons). As in some prior fault-tolerant architectures, the redundancy needed for fault tolerance is obtained by use of multiple processors in one computer. Unlike prior architectures, the multiple processors are embedded in a single field-programmable gate array (FPGA). What makes this new approach practical is the recent commercial availability of FPGAs that are capable of having multiple embedded processors.

Posted in: Semiconductors & ICs, Briefs, TSP

Read More >>

Flexible, Carbon-Based Ohmic Contacts for Organic Transistors

These contacts are printed using an inexpensive, low temperature process. A low-temperature process for fabricating flexible, ohmic contacts for use in organic thin-film transistors (OTFTs) has been developed. Typical drainsource contact materials used previously for OTFTs include (1) vacuum deposited noble metal contacts and (2) solution deposited intrinsically conducting molecular or polymeric contacts. Both of these approaches, however, have serious drawbacks.

Posted in: Semiconductors & ICs, Briefs, TSP

Read More >>

N-Type d Doping of High-Purity Silicon Imaging Arrays

Success depends on details of a low-temperature MBE process. A process for n-type (electron-donor) delta (d) doping has shown promise as a means of modifying back-illuminated image detectors made from n-doped high-purity silicon to enable them to detect high-energy photons (ultraviolet and x-rays) and low-energy charged particles (electrons and ions). This process is applicable to imaging detectors of several types, including charge-coupled devices, hybrid devices, and complementary metal oxide/semiconductor detector arrays.

Posted in: Semiconductors & ICs, Briefs, TSP

Read More >>

Faster Evolution of More Multifunctional Logic Circuits

Evolution is driven to find circuits that perform larger numbers of logic functions. A modification in a method of automated evolutionary synthesis of voltage controlled multifunctional logic circuits makes it possible to synthesize more circuits in less time. Prior to the modification, the computations for synthesizing a four-function logic circuit by this method took about 10 hours. Using the method as modified, it is possible to synthesize a six function circuit in less than half an hour.

Posted in: Semiconductors & ICs, Briefs, TSP

Read More >>