Patent ID: 7374997
Filing Date: 2008-05-20
Classification: H01L

Abstract:
1. A method of manufacturing a flash memory device including a floating gate and control gate, comprising: cleaning a surface of a semiconductor substrate; depositing a nitride film on the semiconductor substrate; performing an oxidization process involving an anneal process in a nitrogen environment to form a silicon oxide film at the interface between the nitride film and the semiconductor substrate, wherein a tunnel oxide film structure, in which the silicon oxide film and the nitride film are layered over one another, is formed over the semiconductor substrate; and forming a gate pattern over the tunnel oxide film, in which the step of forming the gate pattern comprises: depositing a first polysilicon film over the tunnel oxide film to form the floating gate; cleaning a surface of the first polysilicon film; depositing an ONO2 nitride film over the first polysilicon film; performing an oxidization process using an anneal process in a nitrogen environment to form an ONO2 oxide film at the interface between the ONO2 nitride film and the first polysilicon film; depositing an ONO3 oxide film on the ONO2 nitride film to form an ONO dielectric film comprising the ONO2 oxide film, the ONO2 nitride film and the ONO3 oxide film.