An analytical model to predict the short-circuit thermal failure in SOI LDMOS with Linear Doping Profile

The heat generation process inside LDMOS structures accounting for Linear Doping Profile (LDP) or Variation on Lateral Doping (VLD) is analysed in this paper by means of numerical simulation tools and analytical modeling. A uniform heat density, mainly due to the Joule effect, has been demonstrated to be generated in a rectangular shaped heat source, contained in the drift region. The dimensions of such a heat source are dependent on the drain bias as well as on the geometrical /technological structure parameters. Accordingly, we have developed an analytical electro-thermal model to provide physical insight into the heat generation process, arid to predict dynamic temperature distribution by means of heat flow equation approach. The model is suitable for typical high gate bias operation; i.e., when the power dissipation in the drift region is predominant respect to the channel region one.