Low-frequency noise in buried-channel SiGe n-MODFETs

The low-frequency noise and its spatial origin in strained Si/SiGe n-MODFETs with fMAX > 200 GHz is investigated for high-performance analog and mixed-signal applications. The dependence of the low-frequency noise response on two major device design parameters (LG and LSD) is examined. A stronger dependence of 1/f noise on LG compared to LSD is observed. The correlation of drain current noise power spectral density with transconductance suggest carrier number induced fluctuations in the strained silicon channel of SiGe n-MODFETs dominate the noise characteristics. Further investigation of normalized noise spectral density's dependence on gate overdrive voltage confirmed the dominance of carrier number fluctuations in the channel.