Monolithic Preamplifiers Research Articles

Slew-rate removal technique for low-noise front-end preamplifiers

A novel slew-rate removal technique for monolithic front-end preamplifiers for detector readout is presented. It is based on the insertion of a feed-forward path in the gain stage that removes the slew-rate limitation without affecting noise, linearity or stability performances. The paper discusses the design steps of a low-noise high-speed voltage preamplifier in BiCMOS technology and compares the proposed solution with other slew-rate enhancement circuits. The simulated performances in terms of step response, noise, linearity and time-walk are presented and discussed.

Monolithic JFET preamplifier with nonresistive charge reset

This paper shows how a monolithic JFET preamplifier for spectrometry applications can be upgraded by introducing a nonresistive reset. It was found that the charge reset which employs a forward-biased gate-to-source junction of the input JFET suits this case best. The introduction of the nonresistive feedback is important in two respects. First, it puts into better evidence the intrinsic noise limitations of the monolithic preamplifier. Second, it opens up a new perspective in the design of monolithic preamplifiers for very high-resolution X-ray applications.

Cryogenic behavior of low-noise monolithic preamplifiers using a JFET as a front-end element

The noise behavior of monolithic preamplifiers using JFETs as input elements has been investigated on a broad temperature range, from room temperature down to 77 K. The preamplifiers under study are charge integrators intended for use with radiation detectors. The parameter of dominant interest in the analysis is the equivalent noise charge (ENC). The investigation addresses two issues. One is the ENC dependence on temperature. The other one is the extent to which ENC is affected when the preamplifiers are irradiated in cryogenic conditions.

Cryogenic Semiconductor Electronics

The Milan group has centred its activity on cryogenic microelectronics on the use of GaAs MESFET technology. This choice was taken after having found extremely low 1/f noise at 4 K in discrete MESFETs fabricated by NEC and SONY about 20 years ago. Those devices have been discontinued and replaced by equivalent units which nevertheless did not give the same cryogenic performance. A commercial MESFET process has been characterized at cryogenic temperatures, after which FETs and monolithic preamplifier circuits, intended for operation in liquid Helium and liquid Argon, have been designed and fabricated. We will report on our FETs and monolithic preamplifiers which could be of interest for STJ applications. We will briefly review characteristics and results obtained with other technologies which promise new opportunities for the realization of deep cryogenic front-end electronics.

Characteristics of GaAs complementary heterojunction FETs and C-HFET-based amplifiers exposed to high proton fluences

Test results with GaAs CHFETs and CHFET-based monolithic preamplifiers irradiated with up to 5 × 10 14p/cm 2 are reported. The DC and noise characteristics of all transistors were measured before and after irradiation. Additionally, measurements on the DC and AC characteristics of monolithic preamplifiers in CHFET-technology were performed. After the irradiation with 5 × 10 14p/cm 2 all devices are fully functional and show normal behaviour. For a pixel detector with a capacitance of 150 fF connected to an amplifier with an input transistor of 25 μm gate width operating with a drain current density of 0.25 mA/mm, the extrapolated ENC increases from 100 to 120 electrons for a peaking time of 25 ns. In this region of operation, the gate current is still in the order of nA. All measurements of the FETs were performed in the low-power consumption region with drain current densities less than 2 mA/mm.

Neutron irradiation of cold GaAs devices and circuits made with an ion-implanted monolithic process

We have irradiated with neutrons from SARA facility (Grenoble) four versions of cryogenic GaAs monolithic preamplifiers and one MESFET at 87 K. The preamplifiers were designed to readout the ionization signal from the LAr electromagnetic calorimeter of ATLAS experiment. In this paper, data on modification of preamplifier transfer function and degradation of noise performance with irradiation are presented. New preamplifiers (M- and D-versions) exhibited better resistance to irradiation than old C3 version, thanks to a better design of second stage. DC performance of MESFET has been well characterized before and after irradiation. Due to effects of carrier removal and mobility degradation, pinch-off voltage V p and maximum drain current I dss dropped by factor 2.1 and 7.4, respectively, while the transconductance at standing current I d = 8 mA did not change after a fluence of about 13×10 14 neutrons cm 2 (1 MeV equivalent).

JFET-based monolithic preamplifiers for spectrometry applications

A monolithic process has been developed to integrate epitaxial junction field-effect transistors on the same substrate. The process was proven to feature outstanding noise performances on a very broad frequency range. After the first applications to calorimetry front-end in particle physics, the process was oriented to preamplifiers for room temperature radiation spectrometry. This paper describes a new series of low noise monolithic circuits suitable for applications with detector capacitances in the 10–50 pF range.

Monolithic cryogenic preamplifiers based on large gate-area GaAs MESFETs

Monolithic preamplifiers using large gate-area Gallium-Arsenide Metal-Semiconductor Field-Effect Transistors (GaAs MESFETs) at the input have been designed and fabricated using an ion-implanted GaAs process. Large gate-area is necessary to obtain low series noise. A differential voltage-sensitive preamplifier has at the input two MESFETs with a gate width W=6000 /spl mu/m, it is fully DC coupled, has a large common-mode rejection ratio (CMRR) and dissipates low power at 4 K. Dual current-sensitive preamplifiers using at the input MESFETs with W=24000 /spl mu/m, designed for the readout of noble liquid calorimeters, have been integrated in a single chip. Recent tests with a LAr calorimeter prototype demonstrated strong noise reduction compared to previous state-of-the-art hybrid readout circuits. Radiation damage tests have been performed at cold on the current-sensitive preamplifier chips. >

Dynamic and noise performance of large gate area MESFETs made in a monolithic process

Metal-Semiconductor Field Effect Transistors (MESFETs) with gate area up to 48000 /spl mu/m/sup 2/ have been designed and fabricated using an ion-implanted GaAs monolithic process. They have been characterized at 300 K and in particular at 77 K and 4 K as they will be used at the input stage of low-noise preamplifiers for different kinds of cryogenic particle detectors. A single device with W=6000 /spl mu/m has a 1/f noise sufficiently low to substitute it for a group of ten discrete MESFETs of the best quality put in parallel at the input of voltage-sensitive preamplifiers for bolometric detectors. A substantial reduction of noise, with high speed and low power dissipation was obtained in a prototype of a preamplifier designed for LAr calorimetry. Using the SPICE parameters extracted from measurements done on the present FETs, we have designed monolithic low noise preamplifiers for the mentioned applications. The chips are presently under fabrication. >

GaAs MESFETs and monolithic circuits in cryogenic environments

We present the latest results of a research work started in 1986 in Milano, aiming at the optimization of GaAs MESFETs and circuits for cryogenic readout of particle detectors used in experiment of high energy physics. For bolometric detectors we have been looking for low 1/f noise and good dynamic performance at 4 K. We want also fast speed with low white noise and high radiation resistance for the readout of liquid Argon calorimeters. An ion-implanted MESFET process was selected for the realisation of FETs and monolithic preamplifiers for the mentioned applications. The noise and dynamic parameters of the process have been determined for the first time at 4 K and 77 K. SPICE parameters have also been extracted. As a result of this work, monolithic low noise preamplifiers were designed and fabricated. The chips have been tested with a LAr detector at CERN, confirming the expected performance. This chips have been tested with a LAr detector at CERN, confirming the expected performance. Voltage-sensitive preamplifiers for 4 K have also been fabricated and will soon be evaluated. The performance of FETs and monolithic preamplifiers at cryogenic temperatures are reported

Particle identification in a LKr ionization chamber by the [formula omitted] method

Charged particle separation by the dE dx method in a liquid krypton (LKr) ionization chamber has been experimentally studied. The detector has been exposed to pions and protons at the T11 test beam of the CERN PS. Results on particle separation at three different energies are presented. Some results on the performance of monolithic preamplifiers purposely developed to be employed at cryogenic temperatures in calorimetry applications are also presented.

JFET monolithic preamplifier with outstanding noise behaviour and radiation hardness characteristics

A second series of monolithic preamplifiers based on epitaxial channel JFETs and intended for calorimetry at hadron colliders has been realized. The employed buried layer process is upgraded, resulting in a lower pinch-off voltage and a reduced power dissipation. Results are presented on noise, dynamic behavior and radiation damage. New versions of the preamplifier are designed for both large capacitance detectors and for low capacitance pre-shower detectors.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Monolithic junction field-effect transistor charge preamplifier for calorimetry at high luminosity hadron colliders

The outstanding noise and radiation hardness characteristics of epitaxial-channel junction field-effect transistors (JFETs) suggest that a monolithic amplifier based upon them may be able to meet the strict specifications for calorimetry at high luminosity colliders. Results obtained so far with a buried layer planar technology, among them an entire monolithic charge-sensitive preamplifier, are described. The buried layer process seems to have provided a viable approach to the design of monolithic JFET preamplifiers of outstanding noise characteristics. Tests carried out on a preamplifier employing at the input a JFET with 11400- mu m gate width have demonstrated that the noise behavior of the preamplifier is close to that which would be expected if the total noise referred at the preamplifier input were the thermal noise in the input device; that is, the monolithic circuit approaches the noise performances of a hybrid preamplifier using discrete JFETs. >

Monolithic read-out electronics for the silicon calorimeters at SSC/LHC colliders

A very fast monolithic charge sensitive preamplifier using HF2CMOS technology featuring less than 45 mW power dissipation for a 5 V maximum output voltage swing, with a slew rate about 700 V /μ sec for 150 pF input capacitance (≈ 7 nsec rise time), has been realized. A front-end set up for the read out of more detectors and the shaping of the signal with a 20 nsec RC-CR filter employing only monolithic preamplifiers is described and tested. The measured value of ENC (Electronic Noise Charge) for the arrangement with 150 pF input capacitance is 17 ke RMS . The preamplifier meets the requirements for silicon calorimetry application for experiments at the hadron colliders SSC/LHC.

Effects of ionising radiation on the noise properties of electron devices and monolithic circuits

Experiments in elementary particle physics with accelerators of the collider type employ detectors very close to the beam pipe, so that the front-end preamplifiers associated with these detectors are subject to the field of ionising radiation present in the interaction region of the accelerator. The front-end preamplifiers have, accordingly, to be designed with a sufficient degree of radiation tolerance. The present paper aims at discussing some experimental observations concerning the degradation of the noise behaviour of active devices and monolithic preamplifiers after exposure to ionising radiation. Such an experimental analysis led to the design of radiation-tolerant, low noise circuits that will be employed in the Aleph experiment at LEP.

Optimum emitter aspect ratio for bipolar fiber-optic preamplifiers

Many monolithic fiber-optic preamplifiers use a bipolar transistor as the front-end device due to process restraints, despite the relatively poor noise performance of the bipolar transistor. This paper shows that there is an optimum emitter aspect ratio in a bipolar transistor operated at the optimum collector current for noise performance. An expression for this optimum emitter aspect ratio is developed and shown to agree very well with simulation results.

Design and Performance of Monolithic GaAs Direct-Coupled Preamplifiers and Main Amplifiers

The design and performance of a GaAs direct-coupled preamplifier and main amplifier is described. The amplifiers are fabricated by the self-aligned implantation for n/sup +/ -Iayer technology (SAINT) process. The developed preamplifiers have 13-dB gain, 3-GHz bandwidth, and 4.8-dB noise figure for the one-stage amplifier, and 22-dB gain, 2.7-GHz bandwidth, and 5.6-dB noise figure for the two-stage amplifier. The developed four-stage main amplifier has 36-dB gain and 1.5-GHz bandwidth with a power consumption of 710 mW. These amplifiers are promising candidates for application to high-speed data communication systems.