Electron mobility enhancement for mos devices with nitrided polysilicon re-oxidation

Abstract

A semiconductor structure forming method. The PMOS device includes a first gate dielectric on a semiconductor substrate, a first gate electrode on the first gate dielectric, and a first gate spacer along sidewalls of the first gate electrode and the first gate dielectric. The NMOS device includes a second gate dielectric on the semiconductor substrate, a second gate electrode on the second gate dielectric, a nitrided polysilicon re-oxidation layer having a vertical portion and a horizontal portion wherein the vertical portion is on sidewalls of the second gate electrode and the second gate dielectric and wherein the horizontal portion is on the semiconductor substrate, and a second gate spacer on sidewalls of the second gate electrode and the second gate dielectric, wherein the second gate spacer is on the horizontal portion of the nitrided polysilicon re-oxidation layer.

Description

technical field [0001] The present invention relates to a semiconductor device, and in particular to a structure and a manufacturing method of a metal-oxide-semiconductor (MOS) device. Background technique [0002] Polysilicon gates are often used in the process of metal oxide semiconductor devices. In a typical polysilicon gate process, the gate dielectric layer and the polysilicon layer are first formed, and then the gate dielectric layer and the polysilicon layer are patterned to A gate stack composed of a gate dielectric layer and a gate electrode on the gate dielectric layer is formed. [0003] The patterning process of the gate stack may cause damage to the gate electrode and the gate dielectric layer, thereby affecting the integrity of the gate dielectric layer. One situation that occurs is that there is a high electric field in the region of the gate dielectric adjacent to the bottom of the gate electrode, and the affected gate dielectric will create reliability pro...

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Problems solved by technology

[0005] However, the known polysilicon re-oxidation process (polysilicon re-oxidation) brings some adverse effects, such as increasing the channel length and the thickness of the gate dielectric layer, thereby reducing the performance of the MOS device

The reduction in performance includes a reduction in drive current. In order to compensate for the reduction in performance, a nitrided polysilicon re-oxidation process (nitrided polysilicon re-oxidation) can be implemented. In this process, a silicon oxynitride layer is formed to replace the oxide layer. However, the nitrided The polysilicon re-oxidation process is only beneficial for N-type metal oxide semiconductors (NMOS), while the performance of P-type metal oxide semiconductors (PMOS) is reduced

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