Physical characterization of two-dimensional doping profiles for process modeling

Abstract

Physical characterization of doping profiles in two dimensions holds great promise for both high quality analysis of specific structures and for general physical model verification. This latter activity enables the calibration of process simulators and could lead to accurate predictive simulation of modern integrated circuit devices. We used both one- and two-dimensional analytical techniques [secondary-ion-mass spectroscopy (SIMS) and transmission electron microscopy (TEM)] to quantitatively characterize implanted and rapid-thermal-annealed dopant profiles at a polysilicon gate edge. The samples were given self-aligned arsenic implants of 1×1015 ions/cm2 at 35 and 120 keV and at 0° and 20° angles of incidence. The implant was followed by a 30 s/1000 °C rapid thermal anneal. SIMS profiles were used to calibrate 1D simulations and the TEM micrographs in the 1D regions far from the mask edge. Quantitative TEM micrographs near the gate edge were then compared with two-dimensional simulations of final doping distributions, and the implications of discrepancies are discussed.