Title :
High fmax n-type Si/SiGe MODFETs
Author :
Gluck, M. ; Hackbarth, T. ; König, U. ; Haas, A. ; Höck, G. ; Kohn, E.
Author_Institution :
Dept. of Electron. Devices & Circuits, Daimler-Benz AG, Ulm, Germany
fDate :
2/13/1997 12:00:00 AM
Abstract :
The authors report on the fabrication of 0.18 μm gate length n-type Si/Si60Ge40 modulation-doped field-effect transistors (MODFETs) with improved RF performance. The 2D electron gas channel, a strained Si layer grown on a relaxed 2 μm thick graded Si 60Ge40 buffer shows high mobility (μ=1190 cm 2/Vs at room temperature). High DC transconductances (up to 270 mS/mm at room temperature). High saturation currents (260 mA/mm) due to reduced parasitic series resistances (RS⩽0.2 Ωmm) and high carrier densities (ns=1.9×1012 cm-2) are achieved. Very good RF characteristics have been found for the non-recessed device structure with cutoff frequencies up to fT=46 GHz and a record of fmax=81 GHz at low supply voltages around 1.5 V
Keywords :
Ge-Si alloys; elemental semiconductors; high electron mobility transistors; microwave field effect transistors; millimetre wave field effect transistors; semiconductor materials; silicon; two-dimensional electron gas; 0.18 micron; 1.5 V; 270 mS/mm; 2D electron gas channel; 46 GHz; 81 GHz; RF performance; Si-Si60Ge40; Si/Si60Ge40 devices; fabrication; field-effect transistors; modulation-doped FET; n-type Si/SiGe MODFETs; nonrecessed device structure; strained Si layer; thick graded Si60Ge40 buffer;
Journal_Title :
Electronics Letters
DOI :
10.1049/el:19970198
