MODFETs soar to 400 GHz

The operation of MODFETs (modulation-doped FETs) is explained. These devices now have switching delays under 5 ps, current-gain cutoff frequencies of about 250 GHz, and maximum oscillation frequencies in excess of 400 GHz. They also perform frequency division up to 26 GHz. Experimental ring oscillators, frequency dividers, static RAMs, and gate arrays are described. The microwave performance of MODFETs is discussed.<
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