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Proceedings Paper

Performance of a GaAs JFET at cryogenic temperature for faint light detection system
Author(s): Mikio Fujiwara; Masahide Sasaki; Makoto Akiba
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Paper Abstract

A GaAs junction field-effect transistor (JFET) is a promising candidate for low noise at low frequency, and low-power cryogenic electronics to read out high-impedance photo-detectors. We report on the spectral noise characteristics, gate leak current, and gate capacitance of a SONY n-type GaAs JFET at a cryogenic temperature of 4.2 K. In our papers reporting performances of FETs, the noise and leak current have been measured separately. However, noise should be measured in the case of the gate terminal surrounded by high impedance devices, so-called in high impedance circumstance. In such high impedance circumstance, the dielectric polarization noise occurs, which is generated in devices and material around the gate terminal. Materials with dielectric loss generate dielectric polarization noise, which cannot be measured in low impedance circumstance because the electric charges compensate the dipoles. Therefore, to estimate the performance of the FETs for cryogenic readout electronics, noise measurement should be done in high impedance circumstance. In our previous work on a GaAs FET, low noise at low-frequency, i.e. ~500 nV/Hz1/2 at 1 Hz was achieved by the thermal cure (TC) in low-impedance circumstance. By using the thermal curing technique, we have obtained a low noise level of ~500 nV/Hz1/2 at 1Hz. Moreover, we have demonstrated faint light detection at 4.2 K using an InGaAs pin photodiode and a charge integration amplifier composed of the GaAs JFET. We have succeeded in detecting such ultra low power influx as a few photons per second with a quantum efficiency of ~80% and tolerance of 0.5 photons. The leak current of this detection system is ~500 electrons/hour.

Paper Details

Date Published: 29 September 2004
PDF: 8 pages
Proc. SPIE 5499, Optical and Infrared Detectors for Astronomy, (29 September 2004); doi: 10.1117/12.550035
Show Author Affiliations
Mikio Fujiwara, National Institute of Information and Communications Technology (Japan)
Masahide Sasaki, National Institute of Information and Communications Technology (Japan)
Makoto Akiba, National Institute of Information and Communications Technology (Japan)

Published in SPIE Proceedings Vol. 5499:
Optical and Infrared Detectors for Astronomy
James D. Garnett; James W. Beletic, Editor(s)

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