Abstract
On-wafer evaluation of white thermal and shot noise in nanoscale MOSFETs
is demonstrated by directly sensing the drain current under zero- and
nonzsero-drain-bias (Vd) conditions for the first time,
without recourse to a hot noise source, commonly needed in noise figure
measurement. The dependence of white noise intensity on the drain bias
clearly shows thermal noise at Vd=0 V and shot noise at
Vd>0 V with its gate-bias-dependent
suppression. An empirical expression for the Fano factor (shot-noise
suppression factor) that is well-behaved even at Vd=0V
exactly and suitable for measurement-based evaluation is proposed. The
direct measurement approach could allow more accurate and predictive
noise modeling of RF MOSFETs than has conventionally been possible.