Method for Forming A Memory Structure for A 3D NAND Flash Memory

    公开(公告)号:US20250120088A1

    公开(公告)日:2025-04-10

    申请号:US18906994

    申请日:2024-10-04

    Applicant: IMEC VZW

    Abstract: The present disclosure relates to a method that includes forming a layer stack over a substrate; forming first recessed areas in a sidewall surrounding a memory hole in the layer stack by laterally etching back inter-gate spacer layers of the layer stack; forming sacrificial layers in the first recessed areas; forming second recessed areas in the sidewall by laterally etching back gate layers of the layer stack; forming a lateral memory stack in each second recessed area by selectively depositing, in the second recessed areas, a blocking oxide and, subsequently, a charge trap material. The method further includes removing the sacrificial layers by etching from the memory hole; re-growing the inter-gate spacer layers such that the lateral memory stacks are vertically separated by the re-grown inter-gate spacer layers; forming a tunneling oxide layer in the memory hole; and forming a channel layer along the tunneling oxide layer.

    METHODS OF FORMING MEMORY STRUCTURES FOR THREE-DIMENSIONAL NONVOLATILE MEMORY

    公开(公告)号:US20250118547A1

    公开(公告)日:2025-04-10

    申请号:US18906944

    申请日:2024-10-04

    Applicant: IMEC VZW

    Abstract: According to an aspect, a method of forming a memory structure for a 3D NAND flash memory includes forming a layer stack over a substrate, forming first recessed areas in a sidewall surrounding a memory hole in the layer stack by laterally etching back gate layers of the layer stack from the memory hole, and forming a lateral memory stack in each first recessed areas, by depositing a blocking oxide and, subsequently, a charge trap material. The method also includes forming second recessed areas in the sidewall by laterally etching back the inter-gate spacer layers from the memory hole and forming dummy layers in the second recessed areas. The method also includes lining the sidewall of the memory hole with a liner layer, subjecting the dummy layers to a thermal treatment process adapted to convert each dummy layer into an air gap structure, and forming a tunneling oxide layer in the memory hole, along the liner layer, and a channel layer along the tunneling oxide layer.

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