Demonstrating Valence Band-Edge Effective Work Function by Aluminum Implantation in High- k /Metal Gate p -MOSFET with Incorporated Fluorine

This work demonstrates the valence band-edge effective work function ( φ m , eff ) of a titanium nitride (TiN) gate with a hafnium oxide (HfO 2 ) dielectric using a cost-effective, low-complexity gate-first integration scheme. Aluminum (Al) ion implantation following TiN gate stack formation yielded a φ m , eff of 5.0 eV without an equivalent oxide thickness penalty. Additionally, the incorporation of fluorine (F) into the HfO 2 dielectric by the channel implantation approach further improved φ m , eff to 5.1 eV. This technique for modulating φ m , eff has potential for threshold-voltage tuning without any process complexity in high- k /metal gate low-power applications.