Method for manufacturing semiconductor device having hemispherical grain polysilicon film

摘要

A method for forming a hemispherical grain polysilicon layer on an amorphous silicon film increases the surface area of the layer by first forming silicon crystal nuclei on the film, and then enlarging the nuclei before annealing. The nuclei are formed on the amorphous silicon film loading a substrate having the amorphous silicon film into a chamber and injecting a silicon source gas into the chamber at a first, low flow rate which allows the pressure of the chamber to be reduced, thereby increasing the density of the crystal nuclei. A silicon source gas is then injected into the chamber at a second, higher flow rate, thereby enlarging the silicon crystal nuclei on the amorphous layer. The resulting structure is then annealed to form a hemispherical grain polysilicon layer having a large surface area due to the irregular surface of the polysilicon layer. A dielectric layer is then formed on the polysilicon layer, and an impurity-doped polycrystaline silicon layer is deposited over the dielectric layer to form a capacitor.