Effects of elastic stress introduced by a silicon nitride cap on solid-phase crystallization of amorphous silicon

Abstract

Effects of stress on solid-phase crystallization of amorphous silicon (a-Si) were studied by laser Raman spectroscopy. Compressive stress was introduced in a-Si with a Si3N4 cap. The speed of crystallization decreased with the increase of the stress while it increased again with an additional cap of SiO2 on a Si3N4 cap. A SiO2 cap introduced tensile stress in an a-Si film and relaxed compressive stress by a Si3N4 cap. The reason why crystallization of a-Si is suppressed is that the stress is elastic and that it does not relax with crystallization.