Insulator, capacitor with the same and fabrication method thereof, and method for fabricating semiconductor device

A method for fabricating a semiconductor device, comprising:

• forming a first insulating layer on a substrate;
• forming a lower interconnection on the first insulating layer;
• forming a first electrode on the lower interconnection;
• forming an insulator having a laminate structure in which an aluminum oxide (Al2O3) layer and a hafnium oxide (HfO2) layer are laminated on the first electrode alternately in an iterative manner;
• forming a conductive layer on the insulator;
• etching the conductive layer to form a second electrode;
• etching the insulator such that the insulator is left to a predetermined thickness on the first electrode;
• forming a second insulating layer on the substrate including the second electrode and the insulator;
• forming a via connected to each of the first and second electrodes in the second insulating layer;
• and
• forming an upper interconnection connected to the via on the second insulating layer.