A kind of flash storage unit and manufacturing method

Abstract

The invention discloses a flash memory cell and a manufacturing method. The method includes: preparing a shallow trench isolation in a substrate to isolate an active area, and a tunnel oxide layer and a silicon nitride structure are sequentially grown on the active area. ; Performing a widening process on the silicon nitride structure to form a widened silicon nitride structure and a widened area; preparing a first polysilicon structure in the widened area; filling shallow trench isolation; peeling off the widened A silicon nitride structure is formed to form a trench; a second polysilicon structure is grown in the trench, and the second polysilicon structure and the first polysilicon structure form a positive trapezoidal floating gate; and the shallow trench isolation is etched; A silicon oxide barrier layer is prepared on the surface of the shallow trench isolation and the sidewalls and surface of the positive trapezoidal floating gate; a control gate is prepared on the silicon oxide barrier layer. The beneficial effects of the present invention are: reducing the power consumption of the floating gate device and improving the erasing and writing speed and reliability of the flash memory.

Description

technical field [0001] The invention relates to the field of manufacturing semiconductor devices, in particular to a flash memory storage unit and a manufacturing method. Background technique [0002] Flash memory (Flash Memory, referred to as flash memory) is a long-life non-volatile (it can still maintain the stored data information in the case of power failure) semiconductor memory, which is widely used in USB flash drives, flash memory cards, notebooks, etc. Computers, digital cameras, mobile phones and other portable flash memory digital storage products. [0003] The prior art provides a method for manufacturing a flash memory unit. First, an oxide layer and a silicon nitride layer are sequentially formed on a substrate 1, and the oxide layer and the silicon nitride layer are used as a hard mask layer; Etching shallow trenches 2 arranged in parallel on the substrate 1 with a hard film layer, and forming a regular trapezoidal silicon nitride structure and a silicon nit...

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Problems solved by technology

[0004] The method for making the above-mentioned flash memory storage unit has the following disadvantages: due to the instability of the etched shape of the silicon nitride layer, it is easy to cause process defects such as filling gaps in the floating gate when filling the floating gate, and this method fills the gap between the formed floating gate and the control gate. The contact area A is small, resulting in low effective coupling capacitance between the floating gate and the control gate, and the distance between the control gate and the active area is relatively close, and the parasitic coupling capacitance between the control gate and the active area is relatively high, so that the control gate cannot effectively control The opening and closing of the floating gate device causes high power consumption or even failure of the device

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