Metal gate stack and semiconductor gate stack for CMOS devices

• Main Authors: Adams, Charlotte D, Doris, Bruce B, Fisher, Philip, Henson, William K, Sleight, Jeffrey W
• Format: Patent
• Language: English
• Published: 04.10.2011

A semiconductor gate stack comprising a silicon oxide based gate dielectric and a doped semiconductor material is formed on a semiconductor substrate. A high-k material metal gate electrode comprising a high-k gate dielectric and a metal gate portion is also formed on the semiconductor substrate. Oxygen-impermeable dielectric spacers are formed on the sidewalls of the semiconductor gate stack and the high-k material metal gate stack. The oxygen-impermeable dielectric spacer on the semiconductor gate stack is removed, while the oxygen impermeable dielectric spacer on the high-k material metal gate electrode is preserved. A low-k dielectric spacer is formed on the semiconductor gate stack, which provides a low parasitic capacitance for the device employing the semiconductor gate stack.