The curious case of thin-body Ge crystallization

The authors investigate the templated crystallization of thin-body Ge fin structures with high aspect ratios. Experimental variables include fin thickness and thermal treatments, with fin structures oriented in the 110 direction. Transmission electron microscopy determined that various crystal defects form during crystallization of amorphous Ge regions, most notably {111} stacking faults, twin boundaries, and small crystallites. In all cases, the nature of the defects is dependent on the fin thickness and thermal treatments applied. Using a standard 600 °C rapid-thermal-anneal, Ge structures with high aspect ratios crystallize with better crystal quality and fewer uncured defects than the equivalent Si case, which is a cause for optimism for thin-film Ge devices.