A comparison of low- and high-frequency noise spectra of 0.1 micron gate-length conventional, pseudomorphic, and planar-doped MODFET structures

In Modulation-doped FETs and MESFETs. as the gate-length is reduced, the generation-recombination (g-r) noise and 1/f noise spectral intensities usually increase, whereas the thermal noise at high frequencies tends to decrease. Thus the lower corner frequency (f
c
). where the LF noise intercepts with the extrapolated HF noise, moves steadily into higher frequencies. This report shows that, through better device structure design, the impact of LF noise on the microwave and millimeter-wave performance can be minimized. It is also shown that inherently low thermal noise is attainable in MODFETs.