الفهرس 
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Abstract
Abstract
In this thesis, a separately biased second gate is introduced that
covers the entire drift region starting from the intrinsic MOSFET drain
point (internal drain) to the drain of the LDMOSFET device. By
separately biasing the second gate from the main gate, the conductivity of
the drift region can be controlled in a more dynamic way. This helped to
develop a variably controlled ON-resistance and breakdown voltage of
the LDMOSFET device without changing any of the process parameters.
This proposed modification does not greatly affect the manufacturing
cost since it only adds the newly introduced gate metal to the existing
process of the standard LDMOSFET.
A two-dimensional compact model of a double-gate LDMOSFET
is presented in this work. The impact of controlling the drift region
resistance by controlling the bias and/or gate metal work function of a
separately added second gate of the LDMOSFET electrostatics is
investigated. This was done while trading it off with the breakdown
behavior in terms of the surface longitudinal field. Compact models for
the surface potential and surface longitudinal electric field based on the
2D solution of Poisson‟s equation are introduced. The effects of the
second gate on the threshold voltage roll off, are studied in this work.
The introduced models are verified to have good agreement with the
numerical simulation results.
A one-dimensional model has been introduced for the charges,
and current. A study for the effect of the second gate on the currentvoltage
characteristic has been performed. Also a numerical simulation
study has been performed for the capacitances in order to study the effect
of the second gate on the AC behavior of the device.
A self-heating model and numerical simulations have been
performed. It was shown that increasing voltage of gate 2 degrades the
self-heating effect. This is expected as gate 2 acts as an auxiliary drain;
having an effect similar to the drain when increasing its voltage.