Polysilicon capacitor having large capacitance and low resistance and process for forming the capacitor

摘要

A process for forming capacitors in a semiconductor device. In one embodiment, a first insulating layer is deposited on the semiconductor device; a trench is formed in the insulating layer; a first low resistance metal layer is formed covering the interior surface of the trench; a first polysilicon layer is formed over the first low resistance metal layer; a first dielectric layer is formed over the first polysilicon layer; a second polysilicon layer is formed over the first dielectric layer; a second low resistance metal layer is formed over the second polysilicon layer; a third polysilicon layer is formed over the second low resistance metal layer; a second dielectric layer is formed over the third polysilicon layer; a fourth polysilicon layer is formed over the second dielectric layer; a third low resistance metal layer is formed over the fourth polysilicon layer until the trench is filled; the semiconductor device is planarized until the first, second and third low resistance metal layers are exposed above the trench; finally, capacitor leads are formed to the first, second, and third low resistance metal layers.