Vertical NOR memory strings and method for fabrication thereof

A VNOR memory string, comprising:

• a plurality of first and second pillars embedded in multiple composite layers that are formed above a planar surface of a semiconductor substrate, each composite layer comprising an insulator layer and a conductor-containing layer, wherein each conductor-containing layer comprises a conductor and wherein the each of the first pillars and the second pillars comprise a first semiconductor layer of a first conductivity;
• a plurality of third pillars also embedded in the composite layers, each third pillar being formed between a pair of the first and the second pillars;
• a second semiconductor layer of a second conductivity type opposite the first conductivity type provided on the sidewall of each third pillar, the second semiconductor layer contacting both the first and second pillars that are formed on the sides of the respective third pillar;
• a storage layer provided conformally in the conductor-containing layer of each composite layer, such that a portion of the storage layer is provided between the second semiconductor layer and the conductor in each conductor-containing layer, and such that the storage layers of different ones of the composite layers are separated from each other, and each portion of the storage layer encircles the first, second and third pillars within each conductor-containing layer and is separated from different ones of the portions of the storage layer encircling other sets of first, second and third pillars;
• and
• a third insulator layer encircling each of the first and second pillars except at a portion where each of the first and second pillars contacts the respective second semiconductor layer formed on the third pillar, wherein the third insulator layer is provided between the respective first or second pillar and the storage layer without intervening layers.