Semiconductor device and method of manufacturing the same

Abstract

Disclosed is a semiconductor device comprising a semiconductor substrate, a gate electrode, a first insulating film formed between the semiconductor substrate and the gate electrode, and a second insulating film formed along a top surface or a side surface of the gate electrode and including a lower silicon nitride film containing nitrogen, silicon and hydrogen and an upper silicon nitride film formed on the lower silicon nitride film and containing nitrogen, silicon and hydrogen, and wherein a composition ratio N / Si of nitrogen (N) to silicon (Si) in the lower silicon nitride film is higher than that in the upper silicon nitride film.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2002-155740, filed May 29, 2002, the entire contents of which are incorporated herein by reference. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to a semiconductor device and a manufacture method thereof, and in particular, to an insulating film provided in a semiconductor device. [0004] 2. Description of the Related Art [0005] Silicon nitride films (SiN films) are applied to various parts of a semiconductor device. However, conventional SiN films formed using dichlorosilane (SiH2Cl2:DCS) may create various problems when they are used to manufacture next-generation semiconductor devices. [0006] Possible problems with a next-generation DRAM employing a dual gate will be described by way of example. In a next-generation DRAM, a thick SiN film of about 200 nm thickness is used...

AI Technical Summary

Benefits of technology

[0003] The present invention relates to a semiconductor device and a manufacture method thereof, and in particular, to an insulating film provided in a semiconductor device.

Problems solved by technology

However, conventional SiN films formed using dichlorosilane (SiH2Cl2:DCS) may create various problems when they are used to manufacture next-generation semiconductor devices.

However, such measures may degrade the performance of the transistor and are thus difficult to implement.

However, the speed at which the TCS-SiN film is formed, is low and about one-third of that of the DCS-SiN film.

However, it is actually difficult to increase the film formation speed because of the need to keep the film uniform, prevent film quality from being degraded, suppress dusts, and the like.

Consequently, the use of the TCS-SiN film may reduce productivity.

A problem with the MONOS device is destruction of data resulting from write / erase stress.

Further, a problem with NAND type devices is destruction of data resulting from read stress.

Non-volatile memories need to retain charges for 10 years after writes / erases have been carried out 100,000 times. At present, however, data are not sufficiently retained.

However, this structure is not always optimum as described later.

However, the SiN film is a single layer formed using DCS or the like, and this structure is not always optimum.

However, this is not always optimum as described later.

This hinders data from being appropriately retained.

Consequently, this film cannot sufficiently retain data.

However, the use of TCS hinders the film formation speed from being increased, thus reducing productivity.

However, the corresponding conventional structure does not allow data to be sufficiently retained.

However, the corresponding conventional structure does not allow data to be sufficiently retained.

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