Semiconductors & ICs

Some Improvements in Utilization of Flash Memory Devices

Two developments improve the utilization of flash memory devices in the face of the following limitations: (1) a flash write element (page) differs in size from a flash erase element (block), (2) a block must be erased before its is rewritten, (3) lifetime of a flash memory is typically limited to about 1,000,000 erases, (4) as many as 2 percent of the blocks of a given device may fail before the expected end of its life, and (5) to ensure reliability of reading and writing, power must not be interrupted during minimum specified reading and writing times.

Posted in: Semiconductors & ICs, Briefs

Read More >>

T/R Multi-Chip MMIC Modules for 150 GHz

A transmitting gain of 14 dB at 150 GHz has been demonstrated. Modules containing multiple monolithic microwave integrated-circuit (MMIC) chips have been built as prototypes of transmitting/receiving (T/R) modules for millimeter-wavelength radar systems, including phased-array radar systems to be used for diverse purposes that could include guidance and avoidance of hazards for landing spacecraft, imaging systems for detecting hidden weapons, and hazard-avoidance systems for automobiles. Whereas prior landing radar systems have operated at frequencies around 35 GHz, the integrated circuits in this module operate in a frequency band centered at about 150 GHz. The higher frequency (and, hence, shorter wavelength), is expected to make it possible to obtain finer spatial resolution while also using smaller antennas and thereby reducing the sizes and masses of the affected systems.

Posted in: Semiconductors & ICs, Briefs, TSP

Read More >>

InP Heterojunction Bipolar Transistor Amplifiers to 255 GHz

These amplifiers can be used in millimeter-wave imaging systems for weapons detection and airport security, and for radar instruments. Two single-stage InP heterojunction bipolar transistor (HBT) amplifiers operate at 184 and 255 GHz, using Northrop Grumman Corporation’s InP HBT MMIC (monolithic microwave integrated circuit) technology. At the time of this reporting, these are reported to be the highest HBT amplifiers ever created. The purpose of the amplifier design is to evaluate the technology capability for high-frequency designs and verify the model for future development work.

Posted in: Semiconductors & ICs, Briefs

Read More >>

Economical Implementation of a Filter Engine in an FPGA

There are numerous potential uses in general signal processing. A logic design has been conceived for a field-programmable gate array (FPGA) that would implement a complex system of multiple digital state-space filters. The main innovative aspect of this design lies in providing for reuse of parts of the FPGA hardware to perform different parts of the filter computations at different times, in such a manner as to enable the timely performance of all required computations in the face of limitations on available FPGA hardware resources.

Posted in: Semiconductors & ICs, Briefs, TSP

Read More >>

Submillimeter-Wave Amplifier Module With Integrated Waveguide Transitions

This technique can be used in submillimeter-wave imaging in homeland security, weapons detection, and commercial test equipment. To increase the usefulness of monolithic millimeter-wave integrated circuit (MMIC) components at submillimeter-wave frequencies, a chip has been designed that incorporates two integrated, radial E-plane probes with an MMIC amplifier in between, thus creating a fully integrated waveguide module. The integrated amplifier chip has been fabricated in 35-nm gate length InP high-electron-mobility-transistor (HEMT) technology. The radial probes were mated to grounded coplanar waveguide input and output lines in the internal amplifier. The total length of the internal HEMT amplifier is 550 μm, while the total integrated chip length is 1,085 μm. The chip thickness is 50 μm with the chip width being 320 μm.

Posted in: Semiconductors & ICs, Briefs, TSP

Read More >>

Logic Gates Made of N-Channel JFETs and Epitaxial Resistors

Gates could be implemented in SiC ICs for operation at high temperatures. Prototype logic gates made of n-channel junction field-effect transistors (JFETs) and epitaxial resistors have been demonstrated, with a view toward eventual implementation of digital logic devices and systems in silicon carbide (SiC) integrated circuits (ICs). This development is intended to exploit the inherent ability of SiC electronic devices to function at temperatures from 300 to somewhat above 500 °C and withstand large doses of ionizing radiation. SiC-based digital logic devices and systems could enable operation of sensors and robots in nuclear reactors, in jet engines, near hydrothermal vents, and in other environments that are so hot or radioactive as to cause conventional silicon electronic devices to fail.

Posted in: Semiconductors & ICs, Briefs, TSP

Read More >>

Vertical Isolation for Photodiodes in CMOS Imagers

Diffusion cross-talk would be reduced substantially. In a proposed improvement in complementary metal oxide/semi con ductor (CMOS) image detectors, two additional implants in each pixel would effect vertical isolation between the metal oxide/ semiconductor field-effect transistors (MOSFETs) and the photodiode of the pixel. This improvement is expected to enable separate optimization of the designs of the photodiode and the MOSFETs so as to optimize their performances independently of each other. The purpose to be served by enabling this separate optimization is to eliminate or vastly reduce diffusion cross-talk, thereby increasing sensitivity, effective spatial resolution, and color fidelity while reducing noise.

Posted in: Semiconductors & ICs, Briefs

Read More >>