Flash memory device and manufacturing method thereof

Abstract

The invention relates to a flash memory device and a manufacturing method thereof, comprising a source diffusion zone and a drain diffusion zone in an active region of a silicon semiconductor substrate for fixing the distance, a multilayer charge storage layer on the substrate, and a control gate formed on the charge storage layer, wherein, the charge storage layer comprises a tunnel oxide film formed on the silicon semiconductor substrate, a silicon nitride film formed on the tunnel oxide film including a plurality of small crystal by injecting the 14 group elements into the silicon nitride film. The flash memory device maintains a good programme and erasure operation of the SONOS device and improves the trap density and memory window. Owing to the energy barrier difference between the small crystal and the silicon nitride, the electron or cavity captured by the small crystal of the deep trap are not easy to escape so as to improve the data memory performance of the device.

Description

[0001] This application claims the benefit of Korean Patent Application No. 10-2006-0080096 filed on Aug. 23, 2006, the entire contents of which are incorporated herein by reference. technical field [0002] The present invention relates to a semiconductor device, in particular to a flash memory device and a manufacturing method thereof. Background technique [0003] Generally, a flash memory is a type of PROM (Programmable Read Only Memory) that enables data to be rewritable electrically. The flash memory performs a program input method of EPROM (Erasable PROM) and a program erasure method of EEPROM (Electrically Erasable PROM). EPROMs typically have a small cell area because each memory cell is composed of one transistor. However, EPROM has a disadvantage in that data can be erased by UV rays. In contrast, in the case of EEPROM, it is only possible to electrically erase data; but EEPROM has a disadvantage of a large cell area because a memory cell is composed of two tran...

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Problems solved by technology

However, when a SONOS device is used in a flash memory device, the SONOS has limitations due to the following problems

[0008] Due to the low density of well sites remaining in the silicon nitride film, the programming and erasing operation speed is low, thus, it is difficult to obtain a wide memory window

Due to the narrow energy level of the well site remaining in the silicon nitride thin film, the trapped electrons or holes are easily discharged so that the data storage capability deteriorates

Even though a SONOS device can be driven by a low voltage due to trapping electrons or holes in well positions having a low energy level within the silicon nitride thin film, this advantage conversely results in poor data storage capability because electrons or holes are easily de-trapped. shortcoming

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