Thermal profiles and thermal stresses introduced on silicon during scanning line shaped beam annealing

Publisher Website
Google Scholar
Abstract
The evaluation of thermal profiles and introduction of defects due to thermal stesses induced on 〈100〉 silicon during the annealing carried out by the scanning of a line shaped e‐beam source, has been performed. The computation of the temperature profiles along the sample for different beam scan speed and incident power has been used to evaluate the two‐dimensional map of the thermal stresses induced over a 4×2 cm2 silicon sample 〈100〉 oriented. The computed stresses were then compared with the yield stress of the material at the actual annealing temperature. The topographic distribution of the thermal stresses shows quite a complicated trend changing drastically from compressive to tensile as a function of beam position along the sample; it can be concluded that the introduction of defects takes place mainly at the edge of the sample which is irradiated last. An experimental check of our computations has been performed by using a fast multiscanning electron beam along a line, joined to a mechanical translation of the sample through the scanned region. Pyrometric temperature measurements performed during the irradiation confirm our computed temperature profiles, whereas both sheet resistivity measurements and x‐ray topography show that the introduction of defects actually takes place in the region of the sample and at the irradiation conditions foreseen by the present computation.