Method of Forming a Non-volatile Memory Cell Using Off-set Spacers

A method of forming a non-volatile memory cell, comprising:

• forming a first polysilicon layer over but insulated from a semiconductor body region;
• forming a second polysilicon layer over but insulated from the first polysilicon layer whereby the first and second polysilicon layers form a polysilicon stack having a source side and a drain side;
• performing a DDD implant to form a DDD source region in the semiconductor body region along the source side of the polysilicon stack but not along the drain side of the polysilicon stack;
• after the DDD implant, forming off-set spacers along opposing side-walls of the polysilicon stack;
• and
• after forming the offset spacers, performing a source/drain (S/D) implant to form a drain region in the semiconductor body region along the drain side of the polysilicon stack and to form a highly doped region within the DDD source region, the highly doped region being of the same conductivity type as and having a doping concentration greater than the DDD source region, wherein the extent of an overlap between the polysilicon stack and each of the drain region and the highly doped region within the DDD source region is inversely dependent on a thickness of the off-set spacers, and a lateral spacing directly under the polysilicon stack between adjacent edges of the DDD source region and the highly doped region is directly dependent on the thickness of the off-set spacers.