LOW-FREQUENCY NOISE MEASUREMENTS OF ALXGA1-XAS INYGA1-Y AS/GAAS HIGH-ELECTRON-MOBILITY TRANSISTORS/

Low-frequency noise measurements have been performed in the linear ran ge of the I-V characteristics of pseudomorphic Al0.3Ga0.7As/In0.25Ga0. 75As/GaAs high electron mobility transistors (HEMTs) grown by molecula r beam epitaxy with different channel thicknesses. The results obtaine d show that the 1/f noise in such devices depends greatly on channel t hickness. It is controlled by the penetration of the electron wavefunc tion into the barrier as well as by Coulombic effects for thin channel s and by the increase in dislocation concentration for thick ones. Gen eration-recombination (G-R) noise is also present. It is mainly due to real-space transfer of electrons between the two-dimensional electron gas in the channel and the conduction band minimum in the AlxGa1-xAs barrier. Similar results were obtained for the G-R noise of Al0.22Ga0. 78As/In0.20Ga0.8As/GaAs, Al0.3Ga0.7As/GaAs, and Al0.48In0.52As/In0.47G a0.53As/lnP HEMTs. (C) 1995 American Institute of Physics.