3D NAND memory based on two-dimensional material and preparation method thereof

Abstract

The invention belongs to the technical field of semiconductors, and particularly relates to a 3D NAND memory based on a two-dimensional material and a preparation method thereof. In order to solve the problem that an existing 3D NAND memory is poor in electrical performance, a stacked structure of the memory is located on the upper surface of a substrate and is composed of a plurality of insulating layers and conductive layers which are alternately stacked, the conductive layers are located on the upper surface of the substrate, and the conductive layers are located on the upper surface of the substrate. A first annular channel, a second annular channel and a channel hole are concentrically etched on the laminated structure from outside to outside, the second annular channel is communicated with the channel hole, the first annular channel and the second annular channel are filled with insulating media, the channel hole is filled with a semiconductor two-dimensional material, a round hole is etched on the semiconductor two-dimensional material, and the round hole is filled with insulating media. The preparation method comprises the following steps: taking a substrate as a base to obtain a laminated structure with alternate conducting layers and insulating layers, then carrying out two times of annular etching and circular hole etching, and filling corresponding materials in corresponding channels.

Description

technical field [0001] The invention belongs to the technical field of semiconductors, and in particular relates to a 3D NAND memory based on two-dimensional materials and a preparation method thereof. Background technique [0002] 3D NAND memory is a flash memory device with a three-bit stacked structure. Multi-layer data storage units are stacked vertically, and its storage core area is composed of vertical channel tubes with alternately stacked metal gate layers and insulating layers. This technology can construct a storage device with a higher storage capacity, which can accommodate a higher storage capacity in a smaller space. Under the same area condition, the more vertically stacked metal gates, the higher the storage density and capacity of the device. bigger. [0003] Existing 3D NAND memory has problems of poor electrical performance, for example, the on-state current is small and unstable, and the threshold voltage fluctuates greatly. The reason why the 3D NAND ...

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Problems solved by technology

[0004] However, polysilicon material is used as the channel layer because there are crystal boundaries in polysilicon, which will generate charge traps in the channel layer, so that as the number of stacked layers of word lines increases, the on-state current of the memory cell will increase with the number of stacked layers. increase and decrease rapidly, which can lead to dyslexia

[0005] When polysilicon material is used as the channel layer material, a larger on-state current can be achieved by increasing the grain size of polysilicon, however, due to the random distribution of charge traps in polysilicon, the increase in grain size will lead to different memory cells. The fluctuation of the threshold voltage, and the distribution becomes wider, which is easy to cause reliability problems

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