Low-noise Field-effect Transistor Research Articles

Growth of III-V semiconductor crystals under microgravity

The low-gravity environment aboard the space provides a unique platform for both understanding the crystal-growth-related phenomena that are masked by gravity on the earth and exploring new crystal growth techniques. III-V semiconductor crystal growths were carried out under microgravity and the main results include: device-grade semi-insulating GaAs single crystal with improved stoichiometry was grown under microgravity condition, and low noise field-effect transistors and analog switch integrated circuits were fabricated and the performances were better than their terrestrial counterparts; detached Bridgman growth was realized in two model systems of GaSb and InSb by suppressing the hydrostatic pressure of melt, and largely reduced dislocation densities in the materials were observed; the contributions of buoyancy-driven convection, Marangoni convection and rotation magnetic field forced convection on the microscopic segregation were carefully studied; the vertical gradient freezing method was employed to grow semiconductor alloys and chemically homogeneous GaInSb crystal was obtained. In this review, the main progresses in these aspects are summarized and the future challenges are discussed.

Low Noise Field Effect Biosensor with Electrochemically Reduced Graphene Oxide

Reduced graphene oxide, in various configurations has been extensively researched as field effect transistor (FET) biosensor, but they usually exhibit low signal to noise ratio. In this paper, we report the fabrication of low noise FET biosensors with electrochemically reduced graphene oxide(ERGO) on fluorine doped tin oxide(FTO) glass, directly by electrochemical reduction of GO in solution. It has been observed that the sensor is capable of detecting down to1 fM concentration of Hep-B in serum with a dynamic range from 1 fM to 20 pM, linearity of around 95% and current sensitivity of 1.21 mA. Moreover, the signal to noise ratio is around 80 in serum, which is enhanced by more than one order of magnitude compared to the most sensitive reports. Further, the presence of Hep-B can be confirmed by the Lorentzian nature of noise spectra, which makes the detection more precise. The combined advantages of low cost and clean fabrication coupled with sensitive and reliable performance renders the device suitable for point of care diagnostics.

Linear Tunable Analog Front-End Electronics for Silicon Charged-Particle Detectors

A linear front-end electronic system based on a high-speed charge sensitive amplifier and a tunable shaping amplifier suitable for silicon detectors has been presented. The designed charge sensitive amplifier features simplicity and compactness. It is based on the combination of a low-noise field-effect transistor input device and a current feedback opamp ensuring high frequency and small rise time. The circuit provides both an energy signal and a timing signal. The shaping amplifier is a fifth-order complex filter based on an opamp- RC topology providing a nearly Gaussian response. The shaper also includes a pole-zero cancellation circuit and a base line restorer to preclude the pileup of subsequent input signals. A control system has been developed to adjust the main parameters of the channel. The designed readout channel has been optimized for a medium energy range up to 50 MeV coupled to silicon detectors up to 100 pF. Its feasibility for nuclear physics applications has been experimentally validated.

The electronic age: energy-dispersive X-ray analysis and other modern techniques to the present and beyond

This paper summarizes an oral presentation of the same title presented at the occasion of recognizing the “The 100th Anniversary of X-ray Spectroscopy” at DXC 2013. It gives an overview of the development in electronics with focus on (mainly) energy-dispersive X-ray detectors and related data processing. Naturally this has its origin in the early transistors and the first semiconductor junction detectors of the late 1940s. It was followed by refinement of semiconductor detector technology in general and particularly by the invention of Li-drifting and employment of low-noise field effect transistors until such devices matured sufficiently to be marketed by the late 1960s. Further improvement followed in resolution, speed, operability at room temperature, and development of junction arrays with imaging capabilities. An important aspect is the development of related software requiring affordable laboratory computers, programming languages, and databases of fundamental parameters. Today x-ray fluorescence analysis (and not only the energy-dispersive variant) is widely employed as an analytical tool for the traditional technical and industrial applications but notably also, at an expanding rate as well as variety, in other fields including environmental, medical, archaeological, space, arts, and many more.

Updated design for a low-noise, wideband transimpedance photodiode amplifier

The high-speed rotation diagnostic developed for Columbia’s HBT-EP tokamak requires a high quantum efficiency, very low drift detector/amplifier combination. An updated version of the circuit developed originally for the beam emission spectroscopy experiment on TFTR is being used. A low dark current (2nA at 15V bias), low input source capacitance (2pF) FFD-040 N-type Si photodiode is operated in photoconductive mode. It has a quantum efficiency of 40% at the 468.6nm (HeII line that is being observed). A low-noise field-effect transistor (InterFET IFN152 with eNa=1.2nV∕√Hz) is used to reduce the noise in the transimpedance preamplifier (A250 AMPTEK op-amp) and a very high speed (unity-gain bandwidth=200MHz) voltage feedback amplifier (LM7171) is used to restore the frequency response up to 100kHz. This type of detector/amplifier is photon-noise limited at this bandwidth for incident light with a power of >∼2nW. The circuit has been optimized using SIMETRIX 4.0 SPICE software and a prototype circuit has been tested successfully. Though photomultipliers and avalanche photodiodes can detect much lower light levels, for light levels >2nW and a 10kHz bandwidth, this detector/amplifier combination is more sensitive because of the absence of excess (internally generated) noise.

Low-noise readout of superconducting bolometers based on electrothermal feedback

We have developed a simple room-temperature readout for superconducting bolometersand calorimeters. Due to electro-thermal feedback, the bolometer can be noise-matchedwith the readout amplifier. The constructed amplifier consists of low-noise field-effecttransistors, and voltage bias is actively provided by electrical feedback. According to ourmeasurements on superconducting vacuum-bridge bolometers, the total noise islimited by the bolometer phonon and Johnson noise characterized by a criticaltemperature of 8.5 K. We show that, with proper sensor design, it is possible toreach the photon noise limit in video-rate submillimetre imaging applications.

HIGH-FREQUENCY NOISE IN PSEUDOMORPHIC DOUBLE-HETEROJUNCTION HIGH ELECTRON MOBILITY TRANSISTORS

The noise behavior of pseudomorphic double-heterojunction high electron mobility transistors dedicated to power applications is investigated in this paper and compared to conventional low noise field effect transistors. The noise is analyzed from an extrinsic and an intrinsic point of view. It appears that the minimum noise figure is similar for the two devices even if the intrinsic noise sources are different. We explain this phenomenon using the double-heterojunction mode of operation.

Space grown semi-insulating gallium arsenide single crystal and its application

Low noise field effect transistors and analogue switch integrated circuits (ICs) have been fabricated in semi-insulating gallium arsenide (SI-GaAs) wafers grown in space by direct ion-implantation. The electrical behaviors of the devices and the ICs have surpassed those fabricated in the terrestrially grown SI-GaAs wafers. The highest gain and the lowest noise of the transistors made from space-grown SI-GaAs wafers are 22.8 dB and 0.78 dB, respectively. The threshold back-gating voltage of the ICs made from space-grown SI-GaAs wafers is better than 8.5 V. The correlation between the characterizations of materials and devices is studied systematically.

Comparison of field effect transistor characteristics between space-grown and earth-grown gallium arsenide single crystal substrates

Semi-insulating gallium arsenide single crystal grown in space has been used in fabricating low noise field effect transistors and analog switch integrated circuits by the direct ion-implantation technique. All key electrical properties of these transistors and integrated circuits have surpassed those made from conventional earth-grown gallium arsenide. This result shows that device-grade space-grown semiconducting single crystal has surpassed the best terrestrial counterparts.

Low noise field-effect transistor for integrated strain sensing in microelectromechanical systems at 77 K

We have fabricated a strain-sensing field-effect transistor (FET) from a GaAs/AlGaAs heterostructure containint a near surface two-dimensional electron gas. At 77 K the FET shows a typical transconductance of 30 μS and small signal drain-source resistance of 30 MO. The charge noise has a flat spectrum at high frequencies with magnitude 0.7 eHz −1/2and a 1/ fnoise corner of approximately 1 kHz. The strain response, due to the piezoelectric effect, shows a noise limited strain sensitivity <4×10 −9Hz −1/2. Integrated strain sensing FETs offer advantages in small GaAs/AlGaAs microelectromechanical systems.

A direct current superconducting quantum interference device gradiometer with a digital signal processor controlled flux-locked loop and comparison with a conventional analog feedback scheme

A double-washer dc superconducting quantum interference device (SQUID) gradiometer with a flux-locked loop (FLL) based on a digital signal processor (DSP) has been developed for biomagnetic applications. All of the analog electronics in the conventional FLL are replaced and implemented by the DSP except for the low-noise field-effect transistor preamplifier at the front end of the signal recovery components. The DSP performs the signal demodulation by synchronously sampling the recovered signals and applying the appropriate full wave rectification. The signals are then integrated, filtered, and applied to the output. At 4.2 K, the white flux noise of the gradiometer measured in a DSP FLL mode is about 4μΦ0/√Hz and the noise at 1 Hz is 13 μΦ0/√Hz. The corresponding noise levels in the gradiometer operated by the conventional FLL are 1.8 and 3μΦ0/√Hz. The poorer system performance in the DSP FLL compared to the analog FLL is mainly caused by the ambient field noise and interference signals picked up through the connecting cables. Additional noise is also added to the overall noise floor by the instruments employed in the DSP system in the present prototype setup. Further improvement in the noise characteristics and the dynamic behavior of the DSP SQUID gradiometer is expected when a better configuration of DSP with the associated I/O devices is implemented. Additional improvements of the DSP programs are expected by incorporating higher-order integration, adaptive control, and noise reduction schemes.

Verification of on-wafer noise parameter measurements

Using a thin film technology, we have designed and fabricated a new passive device for noise parameter measurement test instrumentation verification. The main feature specifying this device is the same order of magnitude for input-output reflection coefficients and for noise parameters, as for low-noise field effect transistors. This new device is useful as a verification artifact, suited for on-wafer measurements due to its small size and wide operation bandwidth.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Low-noise electronics for semiconductor detectors

Abstract A possible way to attain the best energy resolution of semiconductor detectors is discussed in this report. It is carried out through the matching of detector parameters and parameters of field-effect transistors (FET) of input stages in charge-sensitive preamplifiers (CSP). Four types of low-noise FETs for detectors of various capacitance are presented, the noise response of transistors is discussed. Thin films low-noise feedback resistors with nominals of 10 6 to 10 15 Ω are developed. The energy resolution of various detectors with low-noise electronics is presented.

Low noise cooled microwave amplifiers-simulation and design

The results of a study of cooled low noise field effect transistors and transistor amplifiers are presented. The investigations were made over a broad range of temperature and frequency. The temperature dependence of equivalent circuit elements in the transistor model is reported. This makes it possible to extrapolate with sufficient accuracy the S-parameters up to frequencies where direct measurements are difficult. Suspended microstrip lines have been used in the amplifier designs in order to minimize the losses and to improve the mechanical stability. The results of the theoretical studies are illustrated with a presentation of cooled amplifiers for the ranges 0.5-4 GHz, 3.7-4.1 GHz, 4.8-5.2 GHz, 19-23 GHz and 26-28 GHz, which are designed on the basis of the theoretically obtained parameters. >

Integrated FET and charge reset device for gamma spectrometers

A specially designed and processed five-terminal device incorporating a low-noise field-effect transistor and an integrated charge-restoration mechanism has been used with an HPGe (high-purity germanium) coaxial detector to produce a high-rate, high-resolution gamma spectrometer. A controlled charge pulse is injected into the FET channel and then collected by the gate to discharge the feedback capacitor and reset the amplifier. The reset time is fast, and the high resolution is maintained at energy rate products in excess of 10/sup 11/ eV/s. The FET input capacitance is 8 pF, and the noise voltage is 0.45 nV/ square root Hz at optimum temperature. When it is used with a 22-pF HPGe n-type coaxial detector, the total pulser noise is 420 eV at 12- mu s amplifier peaking time.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Growth and Characterization of GaAs Single Crystals

From a commercial viewpoint, gallium arsenide (GaAs) is currently the leading member of the III-V compound family. Oriented substrates, cut and polished from single-crystal boules, form the materials foundation for a rapidly maturing technology of high speed and high frequency electronic devices and circuits. The initial thrust of GaAs applications was in high powered lasers and light-emitting diodes (LEDs) fabricated on n-type (Si-doped) GaAs wafers grown by the horizontal Bridgman technique. One of the important benefits of using GaAs is the high electron mobility compared to Si. This property has driven the development of low noise and power field-effect transistors (FETs) for microwave applications. The semi-insulating substrate requirement (&gt;107 Ω-cm) was initially met by chromium doping. Currently, the interest is focused on MMIC (microwave monolithic integrated circuits), MIMIC (millimeter microwave ICs), analog ICs for lightwave transmitters and receivers, and digital ICs. The digital circuits have been realized with ion-implanted FETs, selectively doped heterostructure transistors (SDHTs), and heterostructure bipolar transistors (HBTs). Presently, most of the semi-insulating (SI) material processed by the industry is nominally undoped, and grown by the liquid encapsulated Czochralski (LEC) technique. The SI behavior is attained via a delicate balance of deep EL2 donors and carbon acceptors, avoiding chromium in order to eliminate the anomalous out-diffusion and type-conversion associated with this dopant.GaAs wafers up to 4 inches in diameter, with electrical properties homogenized by whole ingot annealing, are currently available from U.S. domestic and overseas suppliers. However, the overall quality is compromised by the large dislocation densities, varying 104 – 105/cm2.

Frequency-shift keyed generation with an optically controlled GaAs field-effect transistor in a surface-acoustic-wave oscillator circuit

A prototype circuit for potential optical integration was developed and evaluated for the generation of frequency-shift keyed (FSK) signals by simultaneously exploiting surface-acoustic wave (SAW) technology and the optical response of the GaAs field-effect transistor (FET).A SAW delay line to be utilized in the feedback path of an oscillator circuit was designed for operation at the fundamental frequency of 111 MHz and operated at its 12th harmonic (1.33 GHz). A low-noise FET was incorporated into the circuit in series with the SAW delay, and a low-power He:Ne laser was focussed through an optical modulator onto the FET structure. The gate bias, which controls the phase shift in the feedback loop of the oscillator, was applied via the open-circuit photovoltage induced at the Schottky-barrier junction of the FET.The optical modulator was driven by a pseudorandom bit generator to obtain FSK generation by the oscillator circuit. Results of the frequency spectrum of the oscillator signal as a function of bit rate and light intensity on the FET were obtained. The successful performance of the circuit indicated that integration of all these elements on GaAs would yield a useful device for FSK signal generation.Un prototype de circuit pour intégration optique potentielle a été développé et évalué pour la génération de signaux FSK (frequency-shift keyed), en exploitant simultanéement la technologie des ondes acoustiques de surface et la réponse optique du transistor GaAs à effet de champ.

2-Gb/s sensitivity of a Ga0.47In0.53As photoconductive detector/GaAs field-effect transistor hybrid photoreceiver

We have measured the 2-Gb/s sensitivity of a photoreceiver consisting of a Ga0.47In0.53As photoconductive detector and a GaAs low-noise field-effect transistor. For a bit error rate of 10−9, the photoconductive receiver shows a sensitivity of −28.8 dBm at 2 Gb/s and 1.51 μm. In view of its high receiver sensitivity and simplicity, the Ga0.47In0.53As photoconductive detector may be attractive for applications in high data rate lightwave communication systems, particularly local area networks.

A simple method for the measurement of the temperature variation of initial magnetic susceptibility between 77 and 1000 K

Two identical multi-layered solenoids each enclosing a water jacket are used in an a.c. bridge circuit so that inclusion of a sample in either coil produces an out of balance signal proportional to the susceptibility of the sample. This signal is then amplified with low noise field effect transistors, converted to direct current with a phase sensitive detector, and displayed against temperature on an XY recorder. The water jacket of one solenoid contains a furnace capable of reaching 700°C, while the other contains a cooling assembly for use between liquid nitrogen and room temperature. The temperature variation of susceptibility allows determination of Curie and transition temperatures.

A low light level slow scan TV camera for satellite application

A short description of the Owl satellite TV camera system and of several unique design features used with the secondary electron conduction (SEC) camera tube is presented. The dependence of the SNR on the scanning speed is analyzed, and the SNR is maximized for an amplifier employing a low noise field-effect transistor. The optimum scanning speed corresponds to an amplifier using a bandwidth of 8 kHz and a gate biasing resistor of a value in excess of 250 MΩ. To satisfy the requirements of optimum scan rate and low data telemetry bandwidth, an intermittent scanning procedure is employed in which the scanning beam touches the unscanned area of the target in a fraction of the scanning time only. This procedure combines the advantages of low noise level and high efficiency charge removal in a single scan. The single exposure scan feature reduces the efficiency of the TV system unless a small bias illumination is applied on the photosensitive surface to avoid the ineffiencies caused by the velocity distribution of the scanning beam.