SONOS memory and preparation method thereof

Abstract

The invention provides a SONOS memory and a preparation method thereof. The method comprises the following steps: providing a semiconductor substrate, orderly forming tunneling oxide layer film and asilicon nitride layer film on the semiconductor substrate from bottom to top; doping germanium ion in the silicon nitride layer film through an ion injection process, thereby forming a germanium nitride thin layer in the silicon nitride film, and forming a composite charge storage layer film of the silicon nitride and the germanium nitride; orderly forming a top oxide layer film and a grid film onthe composite charge storage layer film; etching the grid film, the top oxide layer film, the composite charge storage layer film and the tunneling oxide layer film, and forming the SONOS memory. Thecharge storage layers of the germanium nitride and silicon nitride are used as the charge storage layer in the SONOS memory, the charge capturing and storing capacity are improved, and the data holding capacity of the SONOS memory is improved.

Description

technical field [0001] The invention relates to the field of semiconductor integrated circuit manufacturing, in particular to a SONOS memory and a preparation method thereof. Background technique [0002] Traditional polysilicon floating gate memories use floating gates (floating gate electrodes) to store data, and since doped polysilicon is a conductor, the charges stored in the floating gates are continuously distributed. When the size of the floating gate memory is scaled down, the size of the insulating layer around the floating gate is also reduced accordingly, and the reduction of the size of the insulating layer will cause the electrons in the polysilicon floating gate to be easily lost. When a certain part of the polysilicon floating gate leaks electricity, that is, there is a leakage channel, the charges stored in the entire polysilicon floating gate will be lost through the leakage channel. That is to say, the biggest obstacle restricting the scaling down of float...

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Problems solved by technology

[0004] However, the data retention capability of this SONOS memory structure still needs to be improved

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