Transistor device and fabrication method

摘要

Various embodiments provide transistors and their fabrication methods. An exemplary method for forming a transistor includes removing a dummy gate to form a trench over a semiconductor substrate. A high-k dielectric layer can be conformally formed on surface of the trench and then be fluorinated to form a fluorinated high-k dielectric layer. A functional layer can be formed on the fluorinated high-k dielectric layer and a metal layer can be formed on the functional layer to fill the trench with the metal layer. Due to fluorination of the high-k dielectric layer, negative bias temperature instability of the formed transistor can be reduced and oxygen vacancies can be passivated to reduce positive bias temperature instability of the transistor.

主权项

1. A method for forming a transistor comprising:
providing a semiconductor substrate; forming a dummy gate and an interlayer dielectric layer having a flushed top surface over the semiconductor substrate; removing the dummy gate to form a trench over the semiconductor substrate; forming a high-k dielectric layer over each surface of the trench and the interlayer dielectric layer; fluorinating the high-k dielectric layer to form a fluorinated high-k dielectric layer by a fluorination process, wherein a channel region in the semiconductor substrate under the dummy gate is simultaneously fluorinated in the fluorination process; forming a functional layer on the fluorinated high-k dielectric layer; forming a metal layer on the functional layer to fill the trench with the metal layer; and exposing the interlayer dielectric layer by polishing the metal layer, the functional layer, and the fluorinated high-k dielectric layer on the interlayer dielectric layer.