Epitaxial alignment of arsenic implanted polycrystalline silicon films on 〈100〉 silicon obtained by rapid thermal annealing

We have performed a quantitative analysis of epitaxial quality and arsenic diffusion in ion implanted polycrystalline silicon (polysilicon) layers on 〈100〉 Si, and find a clear advantage for the use of high-temperature rapid thermal annealing (RTA) in the 10-s regime to induce intentional, complete epitaxial alignment. The RTA-induced alignment kinetics and associated arsenic diffusion were studied in the 1050–1150 °C temperature range for arsenic doping concentrations between 1×1020 and 1×1021 cm−3, and were characterized by Rutherford backscattering, ion channeling, and cross-sectional transmission electron microscopy. The information about the relationship between arsenic diffusion, arsenic concentration, and epitaxial quality resulting from a given RTA cycle will be useful for optimizing bipolar transistors with realigned polysilicon emitter contacts.