A computer implemented method for efficiently evaluating a Fourier sine/cosine transform of a bounded analytical function is described. The transform is computed in a plurality of steps which reduces the required transform to a sum of two terms which can be efficiently evaluated using a digital computer. The computer evaluates the first and second terms as definite integrals. The first integral is evaluated via standard techniques, and the second integral is evaluated as a definite integral of a sum of terms which converges. The method is advantageously used to provide a model of semiconductor devices which takes into account quantum mechanical effects while minimizing compute operation time. A look-up table of semiconductor carrier density versus spatially dependent field values can optionally be constructed.