Method to increase the compressive stress of PECVD silicon nitride films

Abstract

The compressive stress of a film layer of a semiconductor device can be controlled using one or more techniques alone or in combination. A first set of embodiments increases the compressive stress of silicon nitride and reduces device defects in devices fabricated with highly compressively stressed silicon nitride films by adding hydrogen to the deposition chemistry. The silicon oxide film layer is formed under the state of hydrogen gas. A silicon nitride film layer may include an initial layer formed in the absence of a hydrogen flow as a base layer for a high stress nitride layer formed in the presence of a hydrogen flow. The silicon nitride film formed according to an embodiment of the present invention may have a compressive stress of 2.8 GPa or higher.

Description

Background technique [0001] During the processing of a substrate to fabricate circuits or displays, the substrate is typically exposed to an excited process gas that deposits materials thereon or etches materials thereon. The chemical vapor deposition (CVD) process uses a process gas excited by a high frequency voltage or microwave energy to deposit material on the substrate, which can be a layer, a contact hole filling, or other selective deposition structures. The deposited layer can be etched or otherwise processed to form active or passive devices on the substrate, such as metal-oxide-semiconductor field effect transistors (MOSFETs) and other devices. A MOSFET generally has a source region, a drain region, and a channel region between the source and drain. In a MOSFET device, a gate electrode is formed above and isolated from the channel by a gate dielectric to control conduction between the source and drain. [0002] The performance of such devices can be improved by re...

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Problems solved by technology

Similar benefits brought about by reducing the thickness of the gate dielectric, such as reduced gate blocking, are limited on small devices due to increased gate leakage current and charge penetration through the dielectric, thus Gradually destroys the transistor

Reducing the supply voltage can reduce the operating power level, but the threshold voltage of the transistor makes the above-mentioned reduction situation also limited

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