Method for increasing utilizable surface of rugged polysilicon layer in semiconductor device

摘要

The present invention is related to a method for increasing utilzable surface area of a rugged polysilicon layer in a semiconductor device. The present method includes steps of: (a) providing a pre-grown rugged polysilicon layer which is composed of polysilicon with first dopants doped therein; (b) forming another polyslicon layer on the pre-grown rugged polysilicon layer; (c) removing a portion of the another polysilicon layer by an anisotropic etching process to expose an upper surface of the pre-grown rugged polysilicon layer; and (d) etching the resulting pre-grown rugged polysilicon layer which an etching selectivity ratio of the pre-grown rugged polysilicon layer to the another polysilicon layer being greater than one, to obtain the rugged polysilicon layer having increasing utilizable surface area. A semiconductor device containing the rugged polysilicon layer created according to the present invention can work well in a relatively dense and small semiconductor chip.