Characterization of RuO2 electrodes on Zr silicate and ZrO2 dielectrics

The rutile stoichiometric phase of RuO2, deposited via reactive sputtering, was evaluated as a gate electrode on chemical vapor deposited ZrO2 and Zr silicate for Si-p-type metal-oxide-semiconductor (PMOS) devices. Thermal an d chemical stability of the electrodes was studied at annealing temperature s of 400, 600, and 800 degreesC in N-2. X-ray diffraction was measured to s tudy grain structure and interface reactions. The resistivity of RuO2 films was 65.0 mu Omega cm after 800 degreesC annealing. Electrical properties w ere evaluated on MOS capacitors, which indicated that the work function of RuO2 was similar to5.1 eV, compatible with PMOS devices. Post-RuO2 gate ann ealing up to 800 degreesC, resulted in only a 1.4 Angstrom equivalent oxide thickness (Tox-eq) change and 0.2 V flatband voltage change for Zr silicat e and a 4 Angstrom Tox-eq change for ZrO2 dielectrics. Tantalum electrodes were also studied on ZrO2 as a comparison of the stability of RuO2 electrod es. (C) 2001 American Institute of Physics.