An analytical breakdown model of high voltage SOI device considering the modulation of step buried-oxide interface charges

Base on solving 2D Poisson equation, an analytical breakdown model of high voltage SOI device with step buried-oxide interface charges (SBIC) is proposed. A new universal RESURF condition of SOI high voltage device with/without the buried-oxide interface charges is derived at the divided region number n from 0 to /spl infin/. By the model, the breakdown characteristics of the new device are discussed for different structure parameters. It is shown that: In the vertical, the electric field of buried oxide layer approaches to the critic value of SiO/sub 2/ 600V//spl mu/m based on the continuity of electric displacement. In the lateral, a uniform profile of the surface electric field is obtained due to the modulation of SBIC. As a result, a very high breakdown voltage is exhibited. The comparisons of analytical results with numerical simulations by MEDICI have been shown a fair agreement.