In this paper, the 2-D analytical models for the surface electrical field and temperature distributions of PB-PSOI devices in terms of Poisson's solution and thermal diffusion solution have been suggested. The analytical results of the presented models show a good agreement with the numerical simulation results obtained by Medici. The dependences of the surface electrical field and temperature on the thickness and the length of the buried oxide have also been discussed in detail. Finally, the methods to optimize the thickness and the length of the buried oxide have been proposed to achieve the high performance of PB-PSOI devices.