Fabrication method of flash memory cell structure

Abstract

A flash memory unit structure comprises a semiconductor substrate. A tunneling oxide layer, a floating gate, an insulating medium layer and a control gate are stacked on the semiconductor substrate in sequence. A checking ion sheath is embedded in the surface of a side wall of the floating gate. The manufacture method of the flash memory unit structure includes the following steps: arranging the tunneling oxide layer and the floating gate on the semiconductor substrate in sequence, arranging the insulating medium layer and the control gate on the floating gate, and embedding checking ions in the side wall of the floating gate to form a checking ion layer of the surface of the side wall of the floating gate. When the floating gate is in a state of keeping charge carriers, the checking ion layer of the side wall of the floating gate increases barrier height of the charge carriers to escape from the floating gate, and thereby durability of the flash memory unit structure for saving information is improved and service life of the flash memory unit structure is prolonged.

Description

【Technical field】 [0001] The invention relates to a semiconductor device structure and a manufacturing method, in particular to a flash memory unit structure and a manufacturing method. 【Background technique】 [0002] Flash memory is a common storage device on the market. Flash memory is a type of programmable read-only memory (PROM) relative to read-only memory (ROM). Flash memory cells in flash memory can retain their stored information for up to ten years without being powered on. [0003] A traditional flash memory cell structure includes a semiconductor base layer, a gate dielectric layer stacked on the semiconductor base layer, a floating gate for storing information, an insulating dielectric layer and a control gate. The flash memory unit recognizes digital information such as "0" or "1" by whether there are stored electrons in the floating gate. In order to improve the ability of the flash memory unit to hold information, the sidewall of the stacked structure part...

AI Technical Summary

Problems solved by technology

When the quality of the insulating layer covering the sidewall of the stacked structure in the flash memory unit is insufficient, it will directly affect the durability of the information stored in the entire flash memory unit, shortening the service life of the entire flash memory device

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