Method for preparing memory device with multilayered capacitor dielectric structure

A method for preparing a memory device, comprising:

• providing a semiconductor substrate having an active region;
• forming a word line extending across the active region;
• forming a first source/drain region and a second source/drain region in the active region and at opposite sides of the word line;
• forming a bit line over and electrically connected to the first source/drain region;
• and
• forming a capacitor over and electrically connected to the second source/drain region, wherein the capacitor comprises a bottom electrode, a top electrode, and a capacitor dielectric structure between the bottom electrode and the top electrode, and
• wherein forming the capacitor dielectric structure comprises forming a first metal oxide layer, forming a second metal oxide layer over the first metal oxide layer, and forming a third metal oxide layer over the second metal oxide layer, and wherein the third metal oxide layer comprises ZrO2 doped with a first dopant selected from the group consisting of Hf, Ta, La, Gd, Y, Sc, Ga, and lanthanide elements.

A method for preparing a memory device, comprising:

• forming a doped region in a semiconductor substrate;
• forming a word line across the doped region such that a first source/drain region and a second source/drain region are formed in the doped region and at opposite sides of the word line;
• forming a bit line over and electrically connected to the first source/drain region;
• and
• forming a capacitor over and electrically connected to the second source/drain region, comprising:
• forming a bottom electrode;
• forming a capacitor dielectric structure over the bottom electrode, comprising:
• forming a first metal oxide layer;
• forming a second metal oxide layer over the first metal oxide layer;
• and
• forming a third metal oxide layer over the second metal oxide layer, wherein the first metal oxide layer, the second metal oxide layer, and the third metal oxide layer comprise materials that are different from each other;
• and
• forming a top electrode over the capacitor dielectric structure.