Metal gate structure of a field effect transistor

Abstract

The invention relates to integrated circuit fabrication, and more particularly to a Field Effect Transistor with a low resistance metal gate electrode. An exemplary structure for a gate electrode for a Field Effect Transistor comprises a lower portion formed of a first metal material having a recess and a first resistance; and an upper portion formed of a second metal material having a protrusion and a second resistance, wherein the protrusion extends into the recess, wherein the second resistance is lower than the first resistance.

Description

[0001] This application is a branch of the invention patent application entitled "Gate electrode for field effect transistor and field effect transistor" with application number 201010185547.5 filed on May 19, 2010 and whose priority date is December 21, 2009. case application. technical field [0002] The present invention relates to an integrated circuit fabrication, and in particular to a method of fabricating a gate structure. Background technique [0003] As transistor dimensions shrink, gate oxide thickness needs to be reduced to maintain performance with reduced gate length. However, in order to reduce gate leakage, a high-k gate dielectric film is used to maintain the same characteristics of known gate oxides used in larger technology nodes. It can have a higher physical thickness at an equivalent thickness. [0004] In addition, as technology nodes shrink, in some integrated circuit designs, metal gate electrodes need to be used to replace conventional polysilicon...

AI Technical Summary

Problems solved by technology

Since the upper portion 128 with a lower resistance value only occupies a small portion of the area of ​​the multi-film metal gate electrode 120a, it can be observed that the multi-film metal gate electrode 120a will exhibit a higher gate Resistor value, which will increase the resistance-capacitance delay (RCdelay) of the circuit and degrade the performance of the device

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