Method for mfg. silicon nitride read-only memory

Abstract

A process for preparing silicon nitride ROM includes generating trapping dielectric sandwiched structure on substrate, which consists of insulating layer, charge trapping layer and insulating layer, generating recess window in said insulating layer and charge trapping layer, and generating thermal oxide layer in it for encoding said charge trapping layer in insulating layer and thermal oxide layer to prevent data loss.

Description

technical field [0001] The present invention relates to a manufacturing method of a memory, and in particular to a manufacturing method of a silicon nitride read only memory (Nitride Read Only Memory, NROM). Background technique [0002] Read-only memory has the characteristics of saving data, so it is widely used. Read-only memory includes mask mode read-only memory (Mask ROM), programmable read-only memory (Programmable ROM, PROM), erasable and programmable Read Only Memory (Erasable Programmable ROM, EPROM), Electrically Erasable Programmable Read Only Memory (Electrically Erasable Programmable ROM, EEPROM), and Flash Erasable Programmable Read Only Memory (Flash EEPROM). [0003] In read-only memory, erasable and programmable read-only memory has the advantages of being programmable, erasable, and can still save data after power failure. For devices that need to be able to save data and update the saved data, For example, the Basic Input Output System (BIOS) in personal...

AI Technical Summary

Problems solved by technology

In the subsequent process of forming the buried drain insulating layer and the control gate, the buried drain insulating layer is affected by the bird's beak effect and forms such as Figure 1C The ellipse shown, and this elliptical buried drain insulating layer pushes the charge trapping layer and the insulating layer on the sidewall of the opening upwards, after depositing the polysilicon layer, the charge trapping layer will be like Figure 1C The position 116 shown is in contact with the polysilicon layer, causing a defect in the device structure

[0011] Although the electrons in the charge trapping layer are concentrated in a local area, they will gradually diffuse with long-term operation. At this time, because the charge trapping layer is in contact with the conductive layer, the electrons will flow into the conductive layer along the connected path, resulting in Loss of stored data

Images