Manufacturing method for ROM array with minimal band-to-band tunneling

A method of manufacturing a read only memory (ROM) array with minimal band-to-band tunneling, the ROM array comprising a core area and a periphery area, the core area having turned on and turned off core transistors and the periphery area having periphery transistors, the method comprising the steps of:

• implanting bit lines into said core area of a substrate as per a later-removed bit line mask;
• providing a ROM oxide layer over the entirety of said substrate;
• etching said ROM oxide layer only from said periphery area as per a later-removed core protect mask;
• providing a gate oxide layer over the entirety of said ROM array whose thickness is dictated by the requirements of the periphery transistors;
• laying down polysilicon rows in said core area as per a polysilicon mask;
• and
• implanting a ROM implant into selected areas of said core area, thereby to produce turned off core transistors,
• wherein the thickness of said ROM oxide layer is dictated by the dosage level of said ROM implant which, in turn, is dictated by the maximal desired band-to-band tunneling current.

A method of manufacturing a read only memory (ROM) array with minimal band-to-band tunneling, the ROM array comprising a core area and a periphery area, the core area having turned on and turned off core transistors and the periphery area having periphery transistors, the method comprising the steps of:

• implanting bit lines into said core area of a substrate as per a later-removed bit line mask;
• providing a ROM oxide layer over the entirety of said substrate;
• etching said ROM oxide layer only from said periphery area as per a later-removed core protect mask;
• providing a gate oxide layer over the entirety of said ROM array;
• laying down polysilicon rows in said core area as per a polysilicon mask;
• and
• implanting a ROM implant into selected areas of said core area, thereby to produced turned off core transistors,
• wherein the thickness of said ROM oxide layer is dictated by the dosage level of said ROM implant which, in turn, is dictated by the maximal desired band-to-band tunneling current.