Investigation of geometry dependence on MOSFET linearity in the impact ionization region using Volterra series

• Device geometry and bias dependence on IMD at breakdown is examined.
• Lower IM3 for shorter gate length MOSFET at breakdown is attributed to nonlinear cancellation.
• Decreased total width reduces IM3 at breakdown due to a more obvious avalanche delay.
• This analysis can benefit CMOS PA designs at breakdown with reliability considered.

In this paper, investigation of device geometry on intermodulation distortion (IMD) of metal–oxide–semiconductor field-effect transistors (MOSFETs) is presented in the impact ionization region based on the Volterra analysis. As the gate length or gate width decreases, observed linearity improvement of the MOSFET in the breakdown regime is attributed to the more obvious breakdown inductance nonlinearity which cancels the transconductance nonlinearity. Linearity of the MOSFETs can be improved by choosing suitable device geometry in the breakdown region. It is believed the presented analysis results can benefit the reliability investigation for MOSFET linearity in the breakdown region.

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