SONOS (Silicon Oxide Nitride Oxide Semiconductor) flash memory unit and formation method thereof

Abstract

The invention provides an SONOS flash memory unit and the formation method thereof. The SONOS flash memory unit comprises a semiconductor substrate, a field effect transistor formed on the semiconductor substrate, a selection gate, a silicon oxide- silicon nitride-silicon oxide layer and a control gate, wherein the channels of the field effect transistor are connected with a source region and a drain region and comprise a first channel region near to the drain region and a second channel region near to the source region; the selection gate is formed on the surface of the first channel region and comprises a gate dielectric layer and a gate electrode on the surface of the gate dielectric layer; the silicon oxide- silicon nitride-silicon oxide layer is at least formed on the surface of the second channel region; and the control gate is formed on the surface of the silicon oxide- silicon nitride-silicon oxide layer. The invention can ensure that the formed SONOS flash memory unit meets the requirements on the read-write performance and the response velocity of a memory array of an embedded system; the SONOS flash memory unit is compatible with the traditional CMOS (Complementary Metal-Oxide-Semiconductor Transistor) technology and has the advantages of simple structure, easy extraction of the interconnection line of the source region and the drain region and convenient memory array formation through wiring integration.

Description

technical field [0001] The invention relates to a flash memory, in particular to a charge trap unit (SONOS) flash memory and a forming method thereof. Background technique [0002] In general, semiconductor memories used to store data are classified into volatile memories and nonvolatile memories, volatile memories are prone to lose their data when power is interrupted, and nonvolatile memories are retained even after the power supply is turned off On-chip information. Compared with other non-volatile storage technologies (eg, disk drives), non-volatile semiconductor memories are characterized by low cost and high density. Therefore, non-volatile memory has been widely used in various fields, including embedded systems, such as PCs and peripherals, telecommunication switches, cellular phones, network interconnection equipment, instrumentation and automotive devices, as well as emerging voice, image , Data storage products such as digital cameras, digital voice recorders an...

AI Technical Summary

Problems solved by technology

[0010] In the existing SONOS flash memory, the gate electrode of the memory cell also plays the role of turning on the MOS transistor to form a conductive channel and controlling the silicon oxide-silicon nitride-silicon oxide layer 102 to store electrons. The read / write performance and response rate have gradually failed to meet the needs of highly integrated memory arrays, especially embedded system memory arrays. On the other hand, the bit lines connected to the source or drain need to lead out interconnect lines from the bottom of the memory cells. Difficulties in routing after device scaling

Images