Process for preparing flash memory

Abstract

A method for manufacturing flash memory. A shallow junction doping step is performed on a substrate with stacked gates as a mask, and shallow junction doped regions are formed in the substrates on both sides of the stacked gates. Next, a mask layer is formed on the substrate, wherein the mask layer covers the surface and sidewalls of the stacked gate, and exposes part of the shallow junction doped region. Then, the substrate is subjected to a deep junction doping step using the mask layer as a mask, and deep junction doping regions are formed in the substrate on both sides of the mask layer. Finally, a thermal process is performed after removing the mask layer to form source / drain regions with shallow drain junctions and deep drain junctions.

Description

technical field [0001] The invention relates to a manufacturing method of a memory, and in particular to a manufacturing method of a flash memory (flash memory). Background technique [0002] Flash memory is a kind of read-only memory (non-volatile memory), which has the advantages of being writable, erasable, and can still save data after power failure. It is a memory component widely used in personal computers and electronic devices. . [0003] The known method of forming a transistor memory cell is to perform an ion doping step on the substrate with the stacked gate as a mask after completing the stacked gate composed of the tunnel oxide layer, floating gate, dielectric layer, control gate, etc., and then After tempering at high temperature and for a long time, a source / drain region with a deep junction is formed. The source / drain region can generate hot electrons in the channel by channel hot electron injection (channel hot electron injection) method after applying an ...

AI Technical Summary

Problems solved by technology

When we use the method of channel hot electron injection to program components, we must supply a large bias voltage to the source / drain, but the substantial bias voltage becomes smaller due to the voltage drop, resulting in a serious loading effect (loading effect)

[0006] To sum up the above, in the case of shrinking component specifications, if a shallow drain junction is used to solve the short channel effect and breakdown leakage current, it will lead to the generation of source / drain loading effect

Conversely, deepening the drain junction in order to solve the loading effect will lead to short channel effect and breakdown leakage current

It can be seen that the known flash memory manufacturing methods cannot solve the problems of short channel effect, breakdown leakage current and load effect at the same time, so that the manufacture of components cannot be effectively reduced.

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