Electrical properties of RuO2 gate electrodes for dual metal gate Si-CMOS

The rutile stoichiometric phase of RuO/sub 2/, deposited via reactive sputtering, was evaluated as a gate electrode for Si-PMOS devices. Thermal and chemical stability of the electrodes was studied at annealing temperatures of 400/spl deg/C and 600/spl deg/C in N/sub 2/. X-ray diffraction patterns were measured to study grain structure and interface reactions. Very low resistivity values were observed and were found to be a strong function of temperature. Electrical properties were evaluated on MOS capacitors, which indicated that the workfunction of RuO/sub 2/ was compatible with PMOS devices. Excellent stability of oxide thickness, flatband voltage and gate current as a function of temperature was also found. Breakdown fields were also measured for the samples before and after annealing.