Analytical model for silicon-on-insulator lateral high-voltage devices using variation of lateral thickness technique

Recently, the variation of lateral thickness (VLT) technique has been proposed as an effective lateral voltage-sustaining technology. However, no analytical model has been reported for exploring the physical mechanism quantitatively. By solving the two-dimensional (2D) Poisson equation, an analytical model for a silicon-on-insulator (SOI) device with a VLT structure is proposed in this paper to optimize the surface potential and electric field distribution of the VLT SOI device. The lateral and vertical breakdown voltages are formulized to quantify the breakdown characteristic. The drift doping concentration range is derived to maximize the breakdown voltage. This model is used to investigate the electric field distribution and breakdown voltage of the VLT SOI device with various parameters. The validity of the proposed model is verified by the fair agreement between the analytical and numerical results.