Hafnium-based aluminate high K metal gate structure based on Si substrate and preparation method of metal gate structure

The invention discloses a hafnium-based aluminate high K metal gate structure based on a Si substrate and a preparation method of the metal gate structure. The problems in the traditional high K metal gate structure that the gate oxide crystallization temperature is low, the gate oxide/substrate interface layer is high in thickness and gate metal ions diffuse to the gate oxide layer, are mainly solved. The high K metal gate structure comprises a hafnium-based aluminate high k gate dielectric film (1), a TiN barrier layer (2), a Ti oxygen adsorption layer (3) and a heavy metal Pt gate electrode (4) on a substrate from bottom to top, wherein the hafnium-based aluminate high k gate dielectric film (1) is 4-10nm in thickness; the TiN barrier layer (2) is 2-3nm in thickness; the Ti oxygen adsorption layer (3) is 4-6nm in thickness; the heavy metal Pt gate electrode (4) is 100-150nm in thickness; the hafnium-based aluminate high k gate dielectric film is of a HfAlO3 or HfO2/Al2O3 laminated structure. The hafnium-ba