Method for improving in-plane uniformity of reliability of SONOS flash device

Abstract

The invention discloses a method for improving the in-plane uniformity of the reliability of a SONOS flash device. The method comprises the following steps: 1) preparing a tunneling oxide layer on a silicon substrate; 2) preparing a silicon nitride layer on the tunneling oxide layer; 3) performing ISSG oxidation on the silicon nitride layer through the RadOx oxidation process to form a silicon oxynitride barrier layer; 4) preparing a silicon nitride trap layer on the silicon oxynitride barrier layer; 5) and performing partial oxidation on the silicon nitride trap layer through the RadOx oxidation process to form a top-layer high-oxygen-containing silicon oxynitride barrier layer. According to the invention, the in-plane uniformity of the reliability of the final SONOS flash device product can be greatly improved; and at the same time, advantages of intuition and convenience can be realized for the control of daily processes.

Description

technical field [0001] The invention relates to a method for improving the reliability of a SONOS flash memory device, in particular to a method for improving the in-plane uniformity of the reliability of the SONOS flash memory device. Background technique [0002] SONOS flash memory devices have become one of the main flash memory types at present because of their good scaling characteristics and radiation resistance characteristics. There are two main reliability issues faced by SONOS flash memory devices: one is the Endurance (electrical erasing endurance) feature, which is to measure the possible degradation of SONOS flash memory devices in terms of device characteristics after multiple programming / erasing; the other is Data Retention The (data retention) feature is the data retention capability of SONOS flash memory devices. Through continuous improvement and the application of many new processes, the reliability of SONOS flash memory devices has been greatly improved....

AI Technical Summary

Problems solved by technology

[0003] However, in the traditional process, the silicon oxynitride barrier layer generally uses N 2 O (nitrogen monoxide) gas doping is formed, but due to N 2 The complete decomposition of O gas requires a higher temperature and is also less controlled, which leads to a very uneven distribution of oxygen content in the silicon oxynitride barrier layer in the ONO film, which greatly affects the in-plane uniformity of the final reliability performance.

At the same time, the HTO high-temperature oxide layer on the top layer of the ONO film is also made of N 2 O acts as a reactive source, therefore, is also subject to N 2 The influence of uneven decomposition of O leads to poor uniformity of the oxide layer, which ultimately affects the partial voltage on the ONO layer during writing, storage, and reading and writing, which in turn affects the reliability performance of SONOS flash memory devices

Images