Channel noise enhancement in small geometry MOSFET and its influence on phase noise calculation of integrated voltage-controlled oscillator

摘要

Channel noise enhancement due to MOSFET scaling and its influence on phase noise estimation of fully integrated VCO have been studied. The channel noise of MOSFET increases due to the hot electron effect of small geometry MOSFET is obvious. The channel noise coefficient, γ, of NMOS is 3.5 for 40-nm gate length, 2.0 for 90-nm gate length in spite of being 2/3 for long channels MOSFET. Simultaneously, calculation of phase noise of fully integrated VCO shows large difference using γ= 2/3 because the part of noise performance of VCO gain-cell depends on channel noise of MOSFET. Calculated phase noise showed good agreement with measured data when the optimum value of channel noise of MOSFET was adopted.