Method of manufacturing flash memory device
AssigneeHynix Semiconductor Inc.
InventorCha Dong
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Abstract
The present invention relates to a method of manufacturing flash memory devices. According to the present invention, an inter-gate insulating film formed between a floating gate and a control gate is formed to have an NONON structure, thus removing the interface of polysilicon and an oxide film. It is thus possible to prevent a thickness of an inter-gate insulating film from increasing due to a subsequent oxidization process. Furthermore, the thickness of the inter-gate insulating film can be kept uniform regardless of the shape of a cell. It is thus possible to make uniform the operating speed among cells and also to reduce the slow program fail rate.
Claims9
A method of manufacturing a flash memory device, comprising the steps of:
- forming a tunneling oxide film and a floating gate on a semiconductor substrate;
- sequentially stacking a first nitride film, a first oxide film, a second nitride film, a second oxide film and a third nitride film on the floating gate to form an inter-gate insulating film;
- and
- forming a control gate on the inter-gate insulating film,
- wherein the first oxide film is formed by oxidizing a surface of the first nitride film.
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Dependencies are inferred from the claim text.