1. A method comprising: determining a relation between model parameters and electrical parameters of integrated circuits by a mapping, wherein the model parameters are configured to be used by a simulation tool; providing a set of electrical parameters, wherein the electrical parameters comprise a first parameter selected from the group consisting essentially of linear threshold voltage Vthlin, linear current Idlin, saturated current Idsat, drain induced barrier lowering DIBL, and combinations thereof; and based on the mapping, using a computer to map the set of electrical parameters to a set of model parameters, wherein the model parameters comprise a second parameter selected from the group consisting essentially of threshold voltage Vth 0 , saturation electron velocity Vsat, mobility U 0 , and DIBL parameter ETA 0 , and combinations thereof.