Forming method of flash memory unit

A flash memory cell and amorphous silicon technology, which is applied in the manufacture of electrical components, electrical solid devices, semiconductor/solid state devices, etc., can solve the problem of the limited number of nanocrystalline silicon particles, the limited number of electrons stored in flash memory cells, and the uneven distribution of nanocrystalline silicon particles. Uniformity and other issues to achieve the effect of increased density, good performance, and high density

CN104299904AActive Publication Date: 2015-01-21SEMICON MFG INT (SHANGHAI) CORP
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2015-01-21
Patent Text Reader

Abstract

The invention discloses a forming method of a flash memory unit. The forming method comprises the following steps: providing a semiconductor substrate; forming a tunneling oxide layer on the semiconductor substrate; forming nanocrystalline silicon particles on the tunneling oxide layer; forming an isolation insulating layer on the tunneling oxide layer and the nanocrystalline silicon particles; and forming a control grid on the isolation insulating layer, wherein the step of forming the nanocrystalline silicon particles on the tunneling oxide layer comprises: forming an amorphous silicon layer on the tunneling oxide layer; and performing repeated seed crystal particle forming processes on the amorphous silicon layer, wherein surface annealing treatment is performed between two adjacent seed crystal particle forming processes, and an annealing process is performed after the last seed crystal particle forming process. The flash memory unit can be used for storing a large quantity of electrons, and has high performance.
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Description

technical field

[0001] The invention relates to the technical field of semiconductor manufacturing, in particular to a method for forming a flash memory unit. Background technique

[0002] In the current semiconductor industry, integrated circuit products are mainly divided into three types: analog circuits, digital circuits, and digital / analog hybrid circuits, among which memory devices are an important type of digital circuits. In recent years, among storage devices, the development of flash memory is particularly rapid. The main feature of the flash memory unit is that it can keep the stored information for a long time without voltage; and it has the advantages of high integration, fast access speed, easy erasing and rewriting, etc. Has been widely used.

[0003] In the existing technology, the flash memory unit includes: a semiconductor substrate, a P-type doped well is formed in the semiconductor substrate; a source and a drain located in the semiconductor substrate, ...

Examples

Embodiment Construction

[0028] The nanocrystalline silicon particles formed by the existing technology are not uniform, and the number of nanocrystalline silicon particles per unit area is limited.

[0029] The method of forming nanocrystalline silicon particles on the tunneling oxide layer in the existing process is: first form an amorphous silicon layer on the tunneling oxide layer, and perform a seed particle formation process on the amorphous silicon layer, and then perform an annealing process . refer to figure 1 , is a graph showing the relationship between the time for performing the seed grain formation process on the amorphous silicon layer and the density of the seed grains on the amorphous silicon layer. Depend on figure 1 It can be seen that the time t for performing the seed particle formation process is greater than 0 and less than or equal to t 1 (that is, the crystal nucleus incubation period), with the increase of time t, the density of seed crystal particles remains basically unc...