Split-gate flash memory unit and manufacturing method thereof

Abstract

The invention discloses a manufacturing method of a split-gate flash memory unit. The method comprises the following steps of: providing a substrate, wherein the substrate comprises at least two first regions and a second region positioned between the two first regions, and a tunneling layer, a silicon nitride layer, a barrier layer and a control grid are formed in sequence on the surface of the substrate in the first regions; forming a groove on the substrate in the second region; forming a spacer medium layer on the surface of the groove, and forming word lines which are filled up the groove, and of which the thicknesses are larger than the depth of the groove; and forming source regions and drain regions for the tunneling layer and the barrier layer in the substrate in the first regions. Correspondingly, the invention further provides a split-gate flash memory unit formed by using the method. According to the split-gate flash unit and the manufacturing method thereof provided by the invention, data are stored by using locally separated charges, so that miniaturization of a device is realized; and moreover, by adopting the split-gate flash unit and the manufacturing method thereof provided by the invention, the programming voltage can be lowered, power consumption is lowered, and the short-channel effect can be overcome.

Description

technical field [0001] The invention relates to the field of semiconductor technology, in particular to a split-gate flash memory unit and a manufacturing 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. Among storage devices, the development of flash memory (flash memory for short) is particularly rapid in recent years. The main feature of flash memory is that it can keep 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., so it has been widely used in many fields such as microcomputer and automatic control. a wide range of applications. [0003] The standard physical structure of flash memory is called a flash cell (bit). The stru...

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Problems solved by technology

[0005] However, the programming voltage of existing split-gate flash memory cells is relatively high, and the miniaturization of devices is limited

In the Chinese patent application whose publication number is CN1881592A, a kind of storage device with SONOS (silicon oxide nitride oxide) structure is proposed, but the above-mentioned problems are still not solved

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