A novel analytical model for the surface field distribution and breakdown voltage of thin-film silicon on insulator (Sol) power MOSFETs has been proposed. The analytical solutions for the surface potential and field distribution are derived on the basis of the two-dimensional Poisson equation. From these expressions, the dependence of breakdown voltage on the device parameters is carefully examined. The validity of this model is demonstrated by comparison with numerical simulations and experimental data. Compared with other analytical models, this approach is more suitable to explain the breakdown behavior. (C) 2004 Elsevier Ltd. All rights reserved.