Oxide-nitride-oxide stack containing a plurality of oxynitrides layers

Abstract

The invention discloses a semiconductor device of an oxide-nitride-oxide (ONO) stack containing a plurality of charge storage layers and a forming method thereof. Generally, the method comprises the following steps of: firstly, forming a first oxide layer on an ONO structure; secondly, forming the plurality of charge storage layers containing nitride on the first oxide layer; and thirdly, forming a second oxide layer in the ONO structure on the plurality of charge storage layers. Preferably, each charge storage layer comprises at least two silicon oxynitride layers with two chemical constitutional ratios of oxygen, nitrogen and / or silicon. More preferably, the ONO structure is a part of a silicon-oxide-nitride-oxide-silicon (SONOS) structure, and the semiconductor device is an SONOS memory transistor.

Description

technical field [0001] The present invention relates to semiconductor manufacturing processes, and more particularly to oxide-nitride-oxide stacks containing improved nitrided oxide or oxynitride layers and methods of forming the same. Background technique [0002] Non-volatile semiconductor memories such as split-gate flash memory generally use stacked floating-gate field effect transistors. In this transistor, electrons are injected into the floating gate of the memory cell to be programmed by biasing the control gate to ground the body region of the substrate on which the memory cell is formed. [0003] An oxide-nitride-oxide (ONO) stack is used as the charge storage layer in silicon-oxide-nitride-oxide-silicon (SONOS) transistors, or as the floating gate in split-gate flash memory and the isolation layer between the control gate. [0004] figure 1 is a cross-sectional view of the intermediate structure of the semiconductor device 100 . Semiconductor device 100 includ...

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Problems solved by technology

Therefore, the charge storage characteristics of the memory 100 including the ONO stack 104, especially the programming and erasing speed and data retention, have the opposite effect.

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