Method of forming capacitor and method of manufacturing DRAM element by using the same

A method of manufacturing a capacitor, the method comprising:

• forming a lower structure on a substrate;
• forming an etch stop layer on the lower structure;
• forming a lower electrode including a first metal on the lower structure, such that the lower electrode extends through the etch stop layer;
• forming a first interface layer including a first metal oxide having conductivity on the lower electrode and the etch stop layer;
• forming a second interface layer including a second metal oxide having conductivity on the first interface layer;
• diffusing a second metal included in the second interface layer to the lower electrodes to form a first interface structure including at least the first metal and the second metal on surfaces of the lower electrodes, the first interface layer and the second interface layer being converted into a second interface structure on the etch stop layer;
• completely removing at least the second interface structure from the etch stop layer through an etching process;
• forming a dielectric layer on the first interface structure and the etch stop layer;
• and
• forming an upper electrode on the dielectric layer.

A method of manufacturing a dynamic random access memory (DRAM) element, the method comprising:

• forming bit line structures on a substrate;
• forming contact structures on the substrate;
• forming an etch stop layer on the contact structures;
• forming lower electrodes including a first metal on the contact structures, respectively, the lower electrodes extending through the etch stop layer to contact the contact structures;
• forming an interface layer having a stacked structure of at least a titanium oxide layer and a niobium oxide layer on the lower electrodes and the etch stop layer;
• diffusing niobium included in the interface layer to the lower electrodes to form a first interface structure including at least titanium and the niobium on surfaces of the lower electrodes and a second interface structure on the etch stop layer;
• completely removing at least the second interface structure from the etch stop layer through an etching process;
• forming a dielectric layer on the first interface structure and the etch stop layer;
• and
• forming an upper electrode on the dielectric layer.