Field effect transistor and production method of spacer structure

Abstract

A method of fabricating a spacer structure which includes forming a dummy gate structure comprising a top surface and sidewall surfaces over a substrate and forming a spacer structure over the sidewall surfaces. Forming the spacer structure includes depositing a first oxygen-sealing layer on the dummy gate structure and removing a portion of the first oxygen-sealing layer on the top surface of the dummy gate structure, whereby the first oxygen-sealing layer remains on the sidewall surfaces. Forming the spacer structure further includes depositing an oxygen-containing layer on the first oxygen-sealing layer and the top surface of the dummy gate structure. Forming the spacer structure further includes depositing a second oxygen-sealing layer on the oxygen-containing layer and removing a portion of the second oxygen-sealing layer over the top surface of the dummy gate structure. Forming the spacer structure further includes thinning the second oxygen-sealing layer.

Description

technical field [0001] The invention relates to the manufacture of an integrated circuit, in particular to a field effect transistor with a spacer structure. Background technique [0002] With the evolution of technology, in some integrated circuit designs, it is necessary to replace the traditional polysilicon gate electrodes with metal gate electrodes to improve the performance of devices with reduced pattern sizes. [0003] A process known as a "gate last" process in which the final gate structure is formed for the metal gate is fabricated at a later stage to reduce subsequent processes (including high temperature processes that must be performed after the gate is formed). Therefore, as the size of transistors decreases, the thickness of the gate oxide layer must be reduced so that the device can maintain device performance even when the gate length is reduced. To reduce gate leakage, the industry also uses high-k dielectric layers, which allow for larger physical thickn...

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Problems solved by technology

For example, any hole 138 in the interlayer dielectric layer 136 can become a storage place for metal in subsequent processes, increasing device instability and / or device failure.

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