Open AccessLight activation of noise at microwave frequencies: a study on scaled gallium arsenide HEMT's
Author(s) -
Caddemi Alina,
Cardillo Emanuele,
Crupi Giovanni
Publication year - 2018
Publication title -
iet circuits, devices and systems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.251
H-Index - 49
ISSN - 1751-8598
DOI - 10.1049/iet-cds.2017.0290
Subject(s) - high electron mobility transistor , noise (video) , noise figure , gallium arsenide , optoelectronics , materials science , noise temperature , microwave , shot noise , noise spectral density , noise generator , y factor , noise measurement , transistor , physics , optics , phase noise , acoustics , noise reduction , voltage , computer science , amplifier , cmos , artificial intelligence , image (mathematics) , quantum mechanics , detector
This study is focused on the experimental investigation of noise at microwave frequencies forscaled gallium arsenide high‐electron‐mobility transistor's (HEMT's). The lightactivation of noise has been achieved by laser exposure in the visible range.The devices have 0.25 μm gate length and 100–200–300 μm gate widths. Their DCcharacteristics, linear scattering and noise parameters were measured both indark condition and under continuous wave light exposure in the 2–18 GHzfrequency range. Previous results had shown a remarkable influence on all theabove‐measured parameters under illumination, with a special concern for thenoise performance. Therefore, the authors investigated the origin of thislight‐activated noise in terms of the intrinsic noise sources, by extracting anoise temperature circuit model for each HEMT.In addition, the noise modelformulation based on the P, R and C as well asthe K g , K r and K c coefficients is used to enlighten the keyaspects of the optically activated noise on the device performance. It isobserved that the degradation of the minimum noise figure can be attributed tothe noise coefficient R, related to the gate noise source that is stronglyaffected by the charge generation related to light exposure.