The invention relates to a preparation method of a nanometer scale W /
TiN composite
refractory metal gate, the steps are as follows: a device source / leakage area
cobalt silicide is formed, after that, the flattening process is carried out, a gate groove is corroded, a gate
silicon oxide is bleached and replaced, then the gate is oxidized again; the vacuum thermal annealing
processing is carried out; a
refractory metal TiN is sputtered, the thickness is 25 to 45nm; a W thin film is sputtered, the thickness is 90 to 110nm; the
acetone and the
anhydrous ethanol are used for ultrasonic cleaning, the deionized water is used for flushing, and the
drying is carried out in hot N2; the W /
TiN T-shaped gate is done with the
lithography; the W / TiN T-shaped gate is etched by reaction ions, the
etching gas is C12 and SF6; a
chemical vapor deposition SiO2 is strengthened by a
plasma, the thickness of SiO2 is 500 to 700nm; a
contact hole is formed; and the
metallizing annealing is carried out. The invention solves a series of serious problems of excessive high
gate resistance, serious
boron penetration of a PMOS device,
polysilicon gate depletion, incompatibility with a high k
gate dielectric and so on which exist in the conventional
polysilicon gate, so the invention can obtain excellent
device properties.