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

Abstract

SUMMARYChannel 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, g; 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 g ¼ 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.

A Study of Striped Inductor for K- and Ka-Band Voltage-Controlled Oscillators

“…Also, the surface current density, J S , and the normalized current density at certain depth x, J X , can be written in Eq. (6).…”

“…However, the lowest phase noise beyond K-and Ka-bands does not follow this 20 dB/dec line as shown in Fig. 1, and the possible reasons for this are considered to be among the following: F has been degraded by MOSFET's channel noise enhancement due to scaling [6], f 1/ f has been degraded by MOSFET's flicker noise enhancement [7], P osc has been degraded by a fall in the power supply due to scaling, or Q tank has been degraded by high frequency operation. In this study, we focus on the cause as the Q factor of the tank circuit degradation beyond K-and Ka-bands.…”