Method of manufacturing charge storage device

Abstract

A method of manufacturing a charge storage device is provided. Utilizing the capacity for a precise control of the thickness and the silicon content of a deposited film in an atomic layer deposition process, a stacked gradual material layer such as a hafnium silicon oxide (HfxSiyOz) layer is formed. The silicon content is gradually changed throughout the duration of the HfxSiyOz deposition process. The etching rate for the HfxSiyOz layer in dilute hydrogen fluoride solution is dependent on the silicon content y in the HfxSiyOz layer. The sidewalls of the stacked gradual material layer are etched to form an uneven profile. The lower electrode, the capacitor dielectric layer and the upper electrode are formed on the uneven sidewalls of the stacked gradual material layers, the area between the lower electrode and the upper electrode is increased to improve the capacitance of the charge storage device.

Dependencies are inferred from the claim text.