Title :
Low-temperature shallow-trap related output-admittance frequency dispersion in AlGaN/GaN MODFETs
Author :
Umana-Membreno, G.A. ; Dell, J.M. ; Nener, B.D. ; Faraone, L. ; Parish, G. ; Wu, Y.F. ; Mishra, U.K.
Author_Institution :
Dept. of Electr. & Electron. Eng., Western Australia Univ., Nedlands, WA, Australia
Abstract :
In this paper we report a study of the output admittance frequency dispersion characteristics of MOCVD-grown Al0.25Ga0.75 N/GaN MODFETs. Our measurements were performed over the frequency range from 20 Hz to 1 MHz, under different biasing conditions (2.5 V<Vds<5.0 V and -1 V<Vg<0 V) and over the temperature range from 77 to 150 K. Depending on the bias conditions, three different activation energies are observed (21.7±0.7 meV, 6.4±0.4 meV and 5.3±0.6 meV) which are attributed to two trapping-centres: the silicon donor in AlGaN, and either surface states in the gate-drain region or interface states at the AlGaN/GaN interface. Additional measurements at high temperatures (600-700 K) indicate the presence of a deep-level trap with an activation energy of approximately 1 eV, in agreement with results reported by others
Keywords :
III-V semiconductors; aluminium compounds; electric admittance; electron traps; gallium compounds; high electron mobility transistors; interface states; surface states; wide band gap semiconductors; 20 Hz to 1 MHz; 77 to 150 K; Al0.25Ga0.75N-GaN; MOCVD; MODFET; bias conditions; deep-level trap; interface states; output-admittance frequency dispersion; shallow-trap; surface states; Admittance; Aluminum gallium nitride; Energy measurement; Frequency measurement; Gallium nitride; HEMTs; MODFETs; Performance evaluation; Temperature dependence; Temperature measurement;
Conference_Titel :
Optoelectronic and Microelectronic Materials Devices, 1998. Proceedings. 1998 Conference on
Conference_Location :
Perth, WA
Print_ISBN :
0-7803-4513-4
DOI :
10.1109/COMMAD.1998.791634
