A novel self-aligned T-shaped gate process for deep submicron Si MOSFET´s fabrication

T-shaped gate electrode is highly desired for high-speed FET fabrication since it can significantly reduce the gate resistance. In this study, we propose and demonstrate a self-aligned method of forming T-shaped gate which is suitable for ULSI Si-MOSFET´s fabrication. This method employs CMP planarization, BOE selective etching and poly-Si sidewall spacer techniques to form the T-shaped poly-Si gate structure. Ti and Co silicidation were also incorporated to demonstrate the effectiveness of this process. Our experimental results indicate that the proposed process not only reduces the parasitic gate resistance, but also improves the thermal stability of the gate structure.