Title :
Metamorphic In0.52Al0.48As/In0.53Ga0.47 As HEMTs on GaAs substrate with fT over 200 GHz
Author :
Dumka, D.C. ; Hoke, W.E. ; Lemonias, P.J. ; Cueva, G. ; Adesida, I.
Author_Institution :
Dept. of Electr. & Comput. Eng., Illinois Univ., Urbana, IL, USA
fDate :
10/14/1999 12:00:00 AM
Abstract :
MBE-grown metamorphic In0.52Al0.48As/In0.53Ga0.47 As HEMTs on GaAs substrates are presented. A linearly-graded InAlGaAs buffer layer is employed for strain relaxation. A mobility of 9520 cm2/Vs and a sheet density of 2.85×1012 cm-2 are achieved at room temperature. Devices with gate lengths ranging from 0.18 to 1.0 μm have been fabricated. Large drain currents and extrinsic transconductances with values up to 900 mA/mm and 1.1 mS/mm, respectively, are reported. For a 0.18 μm gate length device, a unity current gain cutoff frequency (fT) of 204 GHz is obtained. To the authors´ knowledge, this is the highest fT to date for a metamorphic HEMT on GaAs
Keywords :
III-V semiconductors; aluminium compounds; gallium arsenide; high electron mobility transistors; indium compounds; microwave field effect transistors; millimetre wave field effect transistors; molecular beam epitaxial growth; 0.18 to 1 micron; 1.1 mS/mm; 204 GHz; GaAs; GaAs substrate; In0.52Al0.48As-In0.53Ga0.47 As; MBE-grown metamorphic HEMT; drain currents; extrinsic transconductances; gate lengths; linearly-graded InAlGaAs buffer layer; mobility; sheet density; strain relaxation; unity current gain cutoff frequency;
Journal_Title :
Electronics Letters
DOI :
10.1049/el:19991267
