Novel low-temperature recrystallization of amorphous silicon by high-energy ion beam

Abstract

An entirely new beam annealing method that employs a high-energy (∼2.5 MeV) heavy ion (As75, Kr84) beam is presented. With this technology, an amorphous Si layer is recrystallized at below ∼300 °C substrate temperature (much lower than the ordinary solid phase epitaxial growth temperature of ∼600 °C). The temperature just under the beam spot is estimated to be at most ∼20° C higher than that in the surrounding region, because of the large beam spot size (∼10 mmφ) and rapid scan speed (∼104 cm/s). This low-temperature annealing feature is quite different from the case for conventional furnace, laser, electron, and low-energy ion beam annealing. After recrystallization, impurity As atoms are located at substitutional sites with no tetrahedral interstitial components, and are scarcely redistributed.