Semiconductor device

Abstract

The present invention provides a semiconductor device comprising a semiconductor substrate(1), a gate insulating film such as a gate oxide film(2) formed on the substrate, and a gate electrode(3) formed on the insulating film. The gate electrode(3) has a metal compound film(3a) which is formed by CVD using a raw material such as a W(CO)6 gas that contains a metal carbonyl and at least one of an Si-containing gas and an N-containing gas. The work function of the metal compound film(3a) can be controlled by changing the amount of Si and / or N contained therein.

Description

technical field [0001] The present invention relates to a semiconductor device having a MOS structure in which a gate electrode is formed through a gate insulating film on a semiconductor substrate. Background technique [0002] Conventionally, polysilicon (Poly-Si) is used as a gate electrode material of a MOS structure transistor. As a method of controlling the threshold voltage of a MOS structure transistor, there is generally a method of doping a channel region with an impurity called channel doped, or a method of doping a Poly-Si film with an impurity. [0003] However, with the miniaturization of semiconductor devices, there is a problem that the increase of the impurity concentration in the channel region will affect the carrier in the channel doping. In addition, in the Poly-Si doping, due to the oxidation of the substrate gate breakdown of the film, and a depletion layer is formed on the interface between Poly-Si and the gate oxide film of the substrate. Therefore,...

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Problems solved by technology

[0006] This CVD-W film uses, for example, tungsten hexafluoride (WF 6 ) gas is used as a film-forming raw material for film formation. However, in recent years, the design rules have become increasingly finer. When such a gas containing F (fluorine) is used, F will affect the film quality of the gate oxide film of the substrate, and will Deteriorating the gate insulating film

[0007] On the other hand, a metal / silicon stacked gate structure in which a silicon film such as Poly-Si or amorphous silicon is laminated on a metal-containing conductive layer such as a W-based film or a metal-containing conductive layer such as a W-based film is laminated on a silicon film. In the silicon / metal gate structure of the first layer, there is a problem that Si in the silicon film diffuses into the conductive layer containing metal during the high-temperature treatment in the intermediate process, and silicide is formed on the interface between the silicon film and the conductive layer containing metal

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