The semiconductor integrated circuit (IC) industry has experienced rapid growth. Over the course of this growth, functional density of the devices has generally increased by the device feature size.
This scaling down process generally provides benefits by increasing production efficiency, lower costs, and/or improving performance. Such scaling down has also increased the complexities of processing and manufacturing ICs and, for these advances to be realized, similar developments in IC fabrication are needed.
As technology nodes shrink, in some IC designs, the typical polysilicon gate electrode is replaced with a metal gate electrode to improve device performance with the decreased feature sizes. However, there are still quite a few challenges to be handled for the technology of the metal gate electrode.