Analysis of Deep Depletion Effect in SOI LDMOS Substrate with Numerical Simulation

In the paper, the deep depletion (DD) effect in silicon on insulator (SOI) laterally-diffused metal-oxide semiconductor (LDMOS) substrate is analyzed with the device simulation software medici. DD layers appear in the substrate when the device turns off quickly. It gradually decreases with increasing time and eventually disappears in off-state. During this process, charge is distributed in the substrate depletion layer and the electron inversion layer. Distribution of charge changes with time. The electric field in the drift region is affected by the charge distribution of the substrate, which at the source end is continuously weakened, and the drain end is continuously enhanced. The maximum time, in which the device is turned off, and the duration of substrate DD effect decrease with the increase of temperature, the decrease of Shockley-Read-Hall electron and hole lifetime, and the increase of substrate doping concentration.