Method for forming flash memory devices

摘要

A method is provided for fabricating a flash memory device. The method includes providing a semiconductor substrate; and forming a first polysilicon layer. The method also includes forming a hard mask layer; and forming a plurality of first openings exposing the first polysilicon layer in the hard mask layer and the first polysilicon layer. Further, the method includes forming a plurality of grooves by etching the semiconductor substrate along the first openings; and forming liner oxide layers by oxidizing the first polysilicon layer. Further, the method also includes forming shallow trench isolation structures by filling the first openings; and forming second openings by removing the hard mask layer and the non-oxidized first polysilicon layer. Further, the method also includes forming a tunnel oxide layer on a bottom of the second opening; and forming a floating gate on each of the tunnel oxide layers.

主权项

1. A method for fabricating a flash memory device, comprising:
providing a semiconductor substrate; forming a first polysilicon layer on a surface of the semiconductor substrate; forming a hard mask layer on the first polysilicon layer; forming a plurality of first openings to expose the first polysilicon layer in the hard mask layer and first polysilicon silicon layer by etching the hard mask layer and the first polysilicon, forming a plurality of grooves in the semiconductor substrate by etching the semiconductor substrate along the first openings; forming liner oxide layers by oxidizing the first polysilicon layer exposed by the first openings; forming shallow trench isolation structures covering the liner oxide layers by filling the first openings and the grooves with an isolation material; forming second openings by removing the hard mask layer and a non-oxidized first polysilicon layer; forming a tunnel oxide layer on the surface of the semiconductor substrate at a bottom of each of the second openings; and forming a floating gate on each of the tunnel oxide layers.