Method for increasing the capacitance of a trench capacitor

摘要

A method for increasing the trench capacitor surface area is provided. The method, which utilizes a metal silicide to roughen the trench walls, increases capacitance due to the increase in the trench surface area after the silicide has been removed. The roughening of the trench walls can be controlled by varying one or more of the following parameters: the density of the metal, the metal film thickness, the silicide phase, and the choice of the metal. Once the metal is deposited in the trench, the method is self-limited. Shrinking the trench to its original width can be obtained by subsequent silicon deposition or by diffusion of silicon from a cap layer through the silicide.