Capacitor having a tantalum lower electrode and method of forming the same

Abstract

A capacitor has a titanium nitride layer deposited on a silicon substrate for stress reduction and adherence promotion, and a layer of tantalum is deposited thereon. The tantalum layer is oxidized to produce a tantalum pentoxide layer. A top electrode of metal or polysilicon is then deposited on the tantalum pentoxide layer. The top electrode may be made from polysilicon or a similar semiconducting material so that a space charge layer will form in the electrode which will change the rate at which the capacitor charges and discharges. Alternatively, the top electrode may be made from metal to provide an optimal linear response for use in analog applications. Further, an undoped polysilicon layer may be provided above the tantalum pentoxide layer to store charge for non-volatile memory applications. For this purpose, polysilicon can be used to form the top electrode; alternatively, materials such as silicon nitride may be used.

Dependencies are inferred from the claim text.