Split-gate flash memory unit and forming method thereof

Abstract

The invention provides a split-gate flash memory unit and a forming method thereof. The split-gate flash memory unit comprises a semiconductor substrate, a source line polycrystalline silicon layer which is located on the surface of the semiconductor substrate, a source electrode which is located in the semiconductor substrate aligned to the source line polycrystalline silicon layer, a coupling oxide layer and a floating gate which are sequentially located on the semiconductor substrate surfaces at two sides of the source polycrystalline silicon layer, a side wall medium layer which is used for electrically isolating the source wire line polycrystalline silicon from the coupling oxide layer and the floating gate, a coupling oxide layer which is located on the side wall of the floating gate far away from the source line polycrystalline silicon layer, an epitaxial layer which is located on the surface of the semiconductor substrate at one side of the coupling oxide layer far away from the source line polycrystalline silicon layer, tunneling oxide layers which are located on the surface of the epitaxial layer and on the side wall of the side medium layer far away from the source line polycrystalline silicon layer, word line polycrystalline silicon layers which are located on the surfaces of the tunneling oxide layers, and drainage electrodes which are located in the epitaxial layer at one side of the word line polycrystalline silicon layer far away from the floating gate and the semiconductor substrate. With the adoption of the split-gate flash memory unit provided by the invention, the programming efficiency of the split-gate flash memory unit can be improved and the miniaturization is easy to realize.

Description

technical field [0001] The invention relates to the field of semiconductors, in particular to a split-gate flash memory unit and a forming method thereof. Background technique [0002] In the current semiconductor industry, integrated circuit products can be mainly divided into three types: analog circuits, digital circuits and digital / analog hybrid circuits, among which storage devices are an important type of digital circuits. In recent years, among storage devices, a flash memory (flash memory, referred to as a flash memory unit) has developed particularly rapidly. The main feature of the flash memory unit is that it can keep the stored information for a long time without power on; and it has the advantages of high integration, fast access speed, easy erasing and rewriting, etc. Has been widely used. A flash memory unit and its forming method are disclosed in the Chinese patent publication number CN 1606165A. [0003] figure 1 It is a schematic structural diagram of a...

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Problems solved by technology

[0005] The problem solved by the present invention is to provide a split-gate flash memory unit and its forming method to solve the problem that the efficiency of the existing split-gate flash memory unit is not high enough

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