A Compact Model of High-Voltage MOSFET Based on Electric Field Continuity for Accurate Characterization of Capacitance

This article proposes a new compact model of high-voltage MOSFET (HV MOS) to eliminate excessively high capacitance spikes in existing models. In comparison to existing improved methods for capacitance models, the proposed model is no longer based on current continuity between the intrinsic MOS and the drift region models, but rather on electric field continuity, and takes into account the 2-D effects of the drift region caused by shield gate (SG) and contact field plate (CFP). A new point Ki located far away from the SiO2/Si interface is introduced and the electrostatic potential
$\psi _{{\text {Ki}}}$
at point Ki is used to replace the intrinsic drain voltage
${V}_{\text {K}}$
as the drain voltage of the intrinsic MOS to calculate the current and the charge. In addition, we no longer use the 1-D Gaussian equation utilized in most existing models to obtain the surface electrostatic potential
$\psi _{{\text {K}}}$
in the gate–drain overlap (GDO) region, but propose a new
$\psi _{{\text {K}}}$
model considering the impact of the P-body/N-drift junction. The presented model utilizes MM11 to model the current and the charge of the intrinsic MOS, combined with the model of the GDO region charge as a function of
$\psi _{{\text {K}}}$
, which can effectively eliminate excessive capacitance spikes and accurately capture the dc and capacitance characteristics of HV MOS.