Method to remove an oxide seam along gate stack edge, when nitride space formation begins with an oxide liner surrounding gate stack

A method of fabricating a memory device, comprising:

• forming a tunnel oxide layer on a substrate;
• forming a floating gate layer over said tunnel oxide layer;
• forming an oxide/nitride/oxide layer over said floating gate layer;
• forming a control gate layer over said oxide/nitride/oxide layer;
• forming a silicide layer over said control gate;
• forming a cap over said silicide layer to form a gate stack;
• forming a continuous oxide layer over said gate stack and said substrate, said continuous oxide layer having horizontal and vertical portions;
• removing the horizontal portions of said continuous oxide layer;
• forming a first continuous nitride layer over said gate stack, said vertical oxide portions and said substrate, said first continuous nitride layer having horizontal and vertical portions, with each said vertical oxide portion forming an oxide spacer;
• removing the horizontal portions of said first continuous nitride layer, thereby exposing each said oxide spacer at its top end;
• removing a part of said oxide spacer from its top end;
• depositing an amount of nitride sufficient to replace the removed part;
• and
• forming a dielectric layer over said deposited amount of nitride.

A method of fabricating a memory device, comprising:

• forming a tunnel oxide layer on a substrate;
• forming a control gate layer over said tunnel oxide layer;
• forming a silicide layer over said control gate layer;
• forming a cap over said silicide layer to form a gate stack;
• forming a continuous oxide layer over said gate stack and said substrate, said continuous oxide layer having horizontal and vertical portions;
• removing the horizontal portions of said continuous oxide layer;
• forming a first continuous nitride layer over said gate stack, said vertical oxide portions and said substrate, said first continuous nitride layer having horizontal and vertical portions, with each said vertical oxide portion forming an oxide spacer;
• removing the horizontal portions of said first continuous nitride layer, thereby exposing each said oxide spacer at its top end;
• removing a part of said oxide spacer from its top end;
• depositing an amount of nitride sufficient to replace the removed part;
• and
• forming a dielectric layer over said deposited amount of nitride.

A method of fabricating a memory device, comprising:

• forming a continuous oxide layer over a gate stack positioned on a substrate, said continuous oxide layer having horizontal and vertical portions;
• removing the horizontal portions of said continuous oxide layer;
• forming a first continuous nitride layer over said gate stack, said vertical oxide portions and said substrate, said first continuous nitride layer having horizontal and vertical portions, with each said vertical oxide portion forming an oxide spacer;
• removing the horizontal portions of said first continuous nitride layer, thereby exposing each said oxide spacer at its top end;
• removing a part of said oxide spacer from its top end;
• depositing an amount of nitride sufficient to replace the removed part;
• and
• forming a dielectric layer over said deposited amount of nitride.

A method of forming a gate stack structure, comprising:

• providing a device having a gate stack;
• forming a vertical nitride spacer and a vertical oxide spacer on said gate stack, said vertical oxide spacer separating said gate stack from said vertical nitride spacer;
• removing an upper part of said vertical oxide spacer to create a void;
• forming a nitride layer over said device, such that at least a portion of said void is filled by said nitride layer;
• and
• forming a dielectric layer over said nitride layer.