How to form a mos transistor

Abstract

The invention provides an MOS transistor forming method, which comprises the steps of providing a semiconductor substrate; forming a pseudo grid structure on the semiconductor substrate, wherein the two sides of the pseudo grid structure are provided with foot-shaped bottoms; forming an interlayer dielectric layer on the semiconductor substrate at the periphery of the pseudo grid structure, wherein the upper surface of the interlayer dielectric layer is flush with the upper surface of the pseudo grid structure; removing the pseudo grid structure to form a groove, wherein the two sides of the groove are provided with foot-shaped bottom corners; forming an interface layer at the bottom of the groove; forming a high-k dielectric layer at the bottom and the side wall of the groove, wherein the high-k dielectric layer covers the interface layer; forming a first diffusion barrier layer on the high-k dielectric layer; subjecting the part of the first diffusion barrier layer that is right facing the notch part of the groove to ion bombardment treatment through the sputtering process; after the ion bombardment treatment, forming a second diffusion barrier layer on the first diffusion barrier layer. The method improves the performance of an MOS transistor.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a method for forming a MOS transistor. Background technique [0002] With the continuous improvement of the integration of semiconductor devices, when making MOS transistors, using high-k (high dielectric constant) materials as the gate dielectric layer and metal materials as the gate has become the mainstream technology for semiconductor device manufacturing. [0003] Existing MOS transistors with a metal gate-high-k dielectric layer structure can be formed by gate-first and gate-last methods. However, no matter which method is used, the phenomenon of metal diffusion in the metal gate will be encountered. [0004] Especially when aluminum is used as the metal gate, the diffusion of aluminum becomes a major problem in the fabrication of MOS transistors. The diffusion of aluminum will damage the reliability performance of the device, such as damage to the time dependen...

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Problems solved by technology

Moreover, the carrier mobility of the MOS transistor is also reduced due to the diffusion of aluminum, and the device performance is greatly affected.

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