Abstract: A continuous and analytical surface potential model for SOI LDMOS,which accounts for automatic transitions between fully and partially-depleted statuses,is presented.The surface potential equation of the SOI device is solved by using the PSP’s accurate algorithm of surface potential,and the front and back surface potentials are obtained analytically as a function of gate and drain voltage.The formulations of inversion charge and body charge under the fully-depleted state have been modified.The continuous and analytical DC model for SOI LDMOS is given based on PSP.The comparisons between simulation and measurements indicate that this model can predict the DC characteristics of SOI LDMOS accurately.

Key words: SOI, LDMOS, body contact, surface potential, PSP