Flash memory unit and floating gate forming method thereof

Abstract

Provided are a flash memory unit and a floating gate forming method thereof. The floating gate forming method of the flash memory unit comprises the following steps of providing a substrate on which a floating gate layer doped with first type ions is formed; forming a graphical first photoresist on the floating gate layer doped with the first type ions; etching the graphical first photoresist through a dry method, wherein the figure of the first photoresist after etching through the dry method has a smaller dimension than the figure of the first photoresist before etching through the dry method; and performing a second type ion injection to the floating gate layer doped with the first type ions by using the first photoresist after etching through the dry method as a mask layer to form a floating gate layer with a double doped structure, wherein the first type ions is inversed with the second type ions. According to the floating gate of the flash memory unit and the flash memory unit forming method, the flash memory unit that is small in critical dimension and has the double doped floating gate structure can be produced, and the flash memory unit is high in programming efficiency, high in data maintenance capability and low in cost of processing.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a flash memory unit and a method for forming a floating gate thereof. Background technique [0002] Generally speaking, semiconductor memory is divided into volatile memory and non-volatile memory. Volatile memory is prone to lose its data when power is turned off, and non-volatile memory can maintain on-chip information even after power supply is interrupted. [0003] Non-volatile memory includes electrically programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM) and flash memory (flash memory). Compared with other non-volatile memories, flash memory has the characteristics of non-volatile data storage, low power consumption, high integration, fast access speed, easy erasing and rewriting, and low cost. Therefore, it is widely used in various fields. Such as: embedded systems, PCs and peripherals, telecommunications switches,...

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Problems solved by technology

[0008] The present invention solves the problems that in the prior art, it is impossible to form a flash memory unit with a double-doped structure floating gate and a small critical size, and the existing flash memory unit has low programming efficiency, poor data retention, and high process cost.

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