Method for preparing three-dimensional multivalue nonvolatile memory

Abstract

The invention discloses a method for preparing a three-dimensional multivalue nonvolatile memory. The method comprises the following steps of: A, forming a grid lamination structure on a semiconductor substrate; B, forming a grid medium layer; C, forming a channel region and a source / drain doped region; and D, leading a bit line and a word line out of the source / drain doped region and a grid region so as to form three-dimensional integration of the nonvolatile memory. In the method, a plurality of physical storage points are obtained from a single device by comprehensively using a charge local storage property in a charge capture layer and a space characteristic of a vertical stack structure, so that multivalue storage is realized and the three-dimensional integration is formed on a storage device array; therefore, the storage density is increased basically. Meanwhile, the memory prepared by the method has higher device performance, namely programming, erasing, retaining and the like. The process for preparing the three-dimensional multivalue nonvolatile memory is compatible with the conventional silicon plane complementary metal oxide semiconductor (CMOS) process; the conventional storage device array structure integration can be adopted; and the method can be applied widely.

Description

technical field [0001] The invention relates to the technical fields of microelectronics manufacturing and memory, in particular to a method for preparing a multi-value non-volatile memory with three-dimensional integration characteristics and localized charge storage. Background technique [0002] The current microelectronics products are mainly divided into two categories: logic devices and storage devices, and storage devices are needed in almost all electronic products today, so storage devices occupy a very important position in the field of microelectronics. Storage devices can generally be classified into volatile memories and non-volatile memories. The main feature of non-volatile memory is the ability to retain stored information for a long period of time without power on. It not only has the characteristics of read-only memory (ROM), but also has high access speed, and is easy to erase and rewrite, and consumes less power. With the demand for large-capacity and l...

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Problems solved by technology

Patent US5825296 describes a three-dimensional structure read-only memory, and patent US20080023747 discloses the composition and preparation method of a semiconductor storage device array based on a multi-layer structure, but the storage density of the storage array described in these two patents is still biased relative to the actual demand. How to improve the storage density is still an important research direction in the field of non-volatile memory

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