The influence of Al2O3 nanolamination in ALD ZrO2 capacitor on physical and electrical characteristics.

In this paper, the nanolamination of a ZrO₂ insulator by Al₂O₃ for metal insulator metal capacitor applications has been studied. The insulating layers (ZrO₂ and Al₂O₃) were deposited by atomic layer deposition and the electrodes were made of TiN. Different configurations of ZrO₂ and Al₂O₃ alternations were studied, including 1 to 16 Al₂O₃ inclusions in the ZrO₂ layer. X-ray diffraction of the insulator configurations showed that with four or more Al₂O₃ inclusions, the structure loses its crystalline orientation and becomes amorphous. Electrical characterizations have been conducted to study the capacitance, breakdown field, and leakage current for every insulator configuration. The capacitance density significantly decreases as the number of Al₂O₃ layers increases, except when an amorphous transition occurs; at this point, a local maximum of 17 nF/mm² was found. A 19% increase of the breakdown field of samples with two or more Al₂O₃ inclusions has been correlated with an increase of leakage current explained by the emergence of the Fowler–Nordeim conduction mechanism at electrical fields higher than 4 MV/cm. [ABSTRACT FROM AUTHOR]