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Three-dimensional memory device containing separately formed drain select transistors and method of making thereof

  • US 9,922,987 B1
  • Filed: 03/24/2017
  • Issued: 03/20/2018
  • Est. Priority Date: 03/24/2017
  • Status: Active Grant
First Claim
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1. A three-dimensional memory device comprising:

  • an alternating stack of insulating layers and electrically conductive layers located over a substrate;

    at least one drain select level conductive layer located over the alternating stack, wherein each of the at least one drain select level conductive layer comprises electrically conductive line structures that laterally extend along a first horizontal direction and are laterally spaced apart among one another along a second horizontal direction;

    memory stack structures extending through the alternating stack, wherein each of the memory stack structures comprises a memory film and a memory level channel portion contacting an inner sidewall of the memory film; and

    drain select level channel portions vertically extending through the at least one drain select level conductive layer, contacting a respective memory level channel portion, and laterally surrounded by a respective drain select level gate dielectric and a respective one of the electrically conductive line structures at each level of the at least one drain select level conductive layer;

    wherein;

    the memory stack structures are arranged in rows that extend along the first horizontal direction with a first row-to-row pitch along the second horizontal direction across an area including two or more electrically conductive line structures of a same drain select level;

    for each electrically conductive line structure, a respective array of drain select level channel portions extends through the electrically conductive line structure, and drain select level channel portions within the respective array are arranged in at least four rows that extend along the first horizontal direction with a second row-to-row pitch along the second horizontal direction; and

    the second row-to-row pitch is less than the first row-to-row pitch.

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