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Proceedings Paper

Evaluation of cryogenic readout circuits with GaAs JFETs for far-infrared detectors
Author(s): Kenichi Okumura; Iwao Hosako; Makoto Akiba; Norihisa Hiromoto
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Paper Abstract

The characteristics of gallium arsenide junction field- effect transistors (GaAs JFETs) and the performance of cryogenic readout circuits using GaAs JFETs with various gate sizes ranging form W/L equals 5micrometers /0.5micrometers to 200micrometers /200micrometers to systematically measure their static characteristics and low-frequency noise spectra. We found that the low-frequency noise voltage depends on the device size in the saturation region of GaAs JFETs at 4.2 K, and the power density of the noise voltage is inversely proportional to the gate are. These findings allowed us to determine the Hooge parameter of the GaAs JFET at 4.2 K to be 4 by 10-5, assuming that the carrier mobility is 1.5 by 103 cm2/Vs. On the other hand, we did not find the obvious correlation between the low-frequency noise and gate size in the ohmic region of GaAs JFETs. Based on these measurements for GaAs JFETs, we fabricated and tested a dual GaAs JFET, a source-follower-per-detector (SFD) circuit, and a 20 by 3 channel SFD circuit array. The Common-Mode-Rejection-Ratio (CMRR) of the dual GaAs JFET with W/L equals 50micrometers /20micrometers at 4.2 K was determined to be 40-60 dB under small power dissipation. The performance of SFD circuits and 20 by 3 channel SFD arrays for 2D far-IR Ge:Ga detector readouts are currently being evaluated.

Paper Details

Date Published: 16 August 2000
PDF: 7 pages
Proc. SPIE 4008, Optical and IR Telescope Instrumentation and Detectors, (16 August 2000); doi: 10.1117/12.395505
Show Author Affiliations
Kenichi Okumura, Communications Research Lab. (Japan)
Iwao Hosako, Communications Research Lab. (Japan)
Makoto Akiba, Communications Research Lab. (Japan)
Norihisa Hiromoto, Communications Research Lab. (Japan)


Published in SPIE Proceedings Vol. 4008:
Optical and IR Telescope Instrumentation and Detectors
Masanori Iye; Alan F. M. Moorwood, Editor(s)

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