Patent ID: 6140201
Filing Date: 2000-10-31
Classification: H01L

Abstract:
A method for forming a cylinder capacitor of a dynamic random access memory on a provided substrate, the method comprising:forming a first oxide layer on the provided substrate;forming a doped first polysilicon layer on the first oxide layer;patterning the first polysilicon layer without removing the first oxide layer to form a first opening, wherein the first opening exposes the first oxide layer;forming a doped second polysilicon layer on the first polysilicon layer exposed in the first opening;removing a portion of the second polysilicon layer, wherein a remaining portion of the second polysilicon layer forms a first spacer on lateral sides of the first opening;removing a portion of the first oxide layer exposed within the first opening to form a contact opening, wherein the contact opening exposes the provided substrate;forming a doped third polysilicon layer on the second polysilicon layer and in the contact opening;forming a photoresist layer on the third polysilicon layer for patterning a region reserved for forming the cylinder capacitor;etching a portion of the third polysilicon layer outside the photoresist layer to a predetermined depth to form a second opening;removing the photoresist layer;forming a second oxide layer on the third polysilicon layer;removing a portion of the second oxide layer, wherein the remaining second oxide layer forms a second spacer;performing a selective etching process on the third polysilicon layer by using the first polysilicon layer as an etching end point to form a lower electrode;removing the second spacer;depositing a dielectric layer on the lower electrode; anddepositing a forth polysilicon layer on the dielectric as an upper electrode.