Compound material T gate structure for devices with gate dielectrics having a high dielectric constant

摘要

An integrated circuit and process for making the same is provided in which a gate electrode including a gate dielectric and a gate conductor is formed upon a semiconductor substrate. Preferably, the gate dielectric has a dielectric constant greater than the dielectric constant of silicon dioxide. In an embodiment, the gate dielectric is formed from a first compound material, and the gate conductor is formed from a second compound material different from the first compound material. Preferably, the gate dielectric is selectively etched such that a portion of the gate conductor extends beyond sidewall surfaces of the gate dielectric, forming a T-shaped gate electrode. In an embodiment, a first ion implantation is used to form lightly doped drain areas aligned with the gate dielectric sidewall surfaces using a large tilt angle implant. Source and drain implant areas are then formed self-aligned with the sidewalls of opposed sidewall spacers using a second ion implant. Alternatively, the lightly doped drain implant areas and the source/drain implant areas may be formed simultaneously using a single high-energy ion implant. A metal silicide layer may be formed across upper surfaces of the source and drain areas without the need for forming spacers adjacent the gate electrode to prevent silicide bridging.