REnsselaer Computer integrated Circuits Process Engineering (RECIPE) is a two-dimensional (2-D) integrated circuit process modeling program developed for use in VLSI applications. The program incorporates a 2-D diffusion model which includes the concentration dependence of the diffusion coefficients. An incremental solution method is used to compute the appropriate diffusion coefficients as a function of impurity concentration throughout space. RECIPE also incorporates a 2-D ion-implantation model. While intended as a general-purpose modeling program, RECIPE has been used to study channel-length decrease of short-channel MOSFET's during high-temperature processing. A typical phosphorus-implanted (150 keV, 1016/cm2) 1-µm gate transistor had no channel after processing for 60 min at 1000°C, while an arsenic-implanted device had an effective channel length of ∼ 0.1 µm after similar processing.