Method for angular doping of source and drain regions for odd and even NAND blocks
A method for creating NAND flash memory. Source implantations are performed at a first implantation angle to areas between stacked gate structures of a NAND string. Drain implantations are performed at a second implantation angle to areas between the stacked gate structures. The implantations can dope a source line area while not doping a bit line contact area, and providing an additional implantation for the bit line contact area, or dope the bit line contact area while not doping the source line area, followed by an additional implantation for the source line area, or dope neither the source line area nor the bit line contact area, followed by additional implantations for the source line area and the bit line contact area.
1. A method for creating NAND flash memory, comprising:
creating stacked gate structures of a NAND string;
performing source implantation at a first implantation angle to areas between said stacked gate structures;
performing drain implantation at a second implantation angle between said stacked gate structures of said NAND string, said second implantation angle is different than said first implantation angle, said source implantation and said drain implantation include doping a source line area and not doping a bit line contact area for said NAND string; and
performing an additional implantation for said bit line contact area.
2. A method according to claim 1 , wherein:
said additional implantation includes n-type and p-type implantations.
3. A method for creating NAND flash memory, comprising:
creating stacked gate structures of a NAND string;
performing source implantation at a first implantation angle to areas between said stacked gate structures;
performing drain implantation at a second implantation angle between said stacked gate structures of said NAND string, said second implantation angle is different than said first implantation angle, said source implantation and said drain implantation include doping a bit line contact area and not doping a source line area for said NAND string; and
performing an additional implantation for said source line area.
4. A method according to claim 3 , wherein:
said additional implantation includes n-type and p-type implantations.
5. A method for creating NAND flash memory, comprising:
creating stacked gate structures of a NAND string;
performing source implantation at a first implantation angle to areas between said stacked gate structures;
performing drain implantation at a second implantation angle between said stacked gate structures of said NAND string, said second implantation angle is different than said first implantation angle, said source implantation and said drain implantation do not include doping a bit line contact area and do not include doping a source line area for said NAND string; and
performing an additional implantation for said source line area and an additional implantation for said bit line contact area.