Title :
Characterization of flicker noise in GaN-based MODFET´s at low drain bias
Author :
Ho, W.Y. ; Surya, Charles ; Tong, K.Y. ; Kim, Wook ; Botcharev, Andrei E. ; Morkoç, Hadis
Author_Institution :
Dept. of Electron. Eng., Hong Kong Polytech., Kowloon, Hong Kong
fDate :
6/1/1999 12:00:00 AM
Abstract :
We report systematic characterizations of flicker noise in GaN based MODFET´s. The devices were fabricated by MBE on (0001) basal plane sapphire substrates with an 800 Å AlN buffer layer grown at 800°C. Flicker noise was measured across the channel of the devices from room temperature to about 130 K. The voltage noise power spectra, S V(f), were found to be proportional to 1/fγ. The frequency exponent, γ, of SV(f) exhibits systematic dependencies on the device temperature as well as the gate bias, VG . The variation of the noise power spectra as a function of the drain voltage, VD, and the gate bias, VG, were studied in detail and were found to vary as VD2/(V G-VT)β where β changes with temperature from about 2.1 at room temperature to about 0.9 at 130 K. Analyses of the data show that the noise originated from the thermal activation of carriers to the localized states at the AlGaN/GaN heterointerface in the channel area. The data suggested that the trapping and detrapping of carriers did not lead to fluctuations in the carrier concentration as postulated in the McWhorter´s model. However, more work is needed to determine if surface mobility fluctuations played a key role in the 1/f noise
Keywords :
1/f noise; III-V semiconductors; aluminium compounds; carrier density; carrier mobility; electron traps; flicker noise; gallium compounds; high electron mobility transistors; molecular beam epitaxial growth; semiconductor device noise; semiconductor epitaxial layers; 1/f noise; 293 to 130 K; 800 angstrom; 800 degC; AlGaN-GaN; MBE; MODFET; carrier concentration; detrapping; device temperature; drain bias; flicker noise; frequency exponent; localized states; surface mobility fluctuations; thermal activation; trapping; voltage noise power spectra; 1f noise; Buffer layers; Fluctuations; Gallium nitride; HEMTs; MODFETs; Noise measurement; Power measurement; Temperature; Voltage;
Journal_Title :
Electron Devices, IEEE Transactions on