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The development and implementation of a metal gate technology (alloy, compound, or silicide) into metal-oxide-semiconductor field effect transistors (MOSFETs) is necessary to extend the life of planar CMOS devices and enable further downscaling. This thesis examines possible metal gate materials for improving the performance of the gate stack and discusses process integration as well as improved electrical and physical measurement methodologies, tested on capacitor structures and transistors.

By using reactive PVD and gradually increasing the N₂/Ar flow ratio, it was found that the work function (on SiO₂) of the TiN_x and ZrN_x metal systems could be modulated ~0.7 eV from low near nMOS work functions to high pMOS work functions. After high-temperature anneals corresponding to junction activation, both metals systems reached mid-gap work function values. The mechanisms behind the work function changes are explained with XPS data and discussed in terms of metal gradients and Fermi level pinning due to extrinsic interface states.

A modified scheme for improved Fowler-Nordheim tunnelling is also shown, using degenerately doped silicon substrates. In that case, the work functions of ALD/PVD TaN were accurately determined on both SiO₂ and HfO₂ and benchmarked against IPE (Internal Photoemission) results. KFM (Kelvin Force Microscopy) was also used to physically measure the work functions of PVD TiN and Mo deposited on SiO₂; the results agreed well with C-V and I-V data.

Finally, an appealing combination of novel materials is demonstrated with ALD TiN/Al₂O₃/HfAlO_x/Al₂O₃/strained-SiGe surface channel pMOS devices. The drive current and transconductance were measured to be 30% higher than the Si reference, clearly demonstrating increased mobility and the absence of polydepletion. Finally, using similarly processed transistors with Al₂O₃ dielectric instead, low-temperature water vapour annealing was shown to improve the device characteristics by reducing the negative charge within the ALD Al₂O₃.

The demands for faster, smaller, and less expensive electronic equipments are basically the driving forces for improving the speed and increasing the packing density of microelectronic components. Down-scaling of the devices is the principal method to realize these requests. For future CMOS devices, new materials are required in the transistor structure to enable further scaling and improve the transistor performance.

This thesis focuses on novel metal gate and high-κ dielectric materials for future CMOS technologies. Specifically, TiN and ZrN gate electrode materials were studied with respect to work function and thermal stability. High work function, suitable for pMOS transistors, was extracted from both C-V and I-V measurements for PVD and ALD TiN in TiN/SiO₂/Si MOS capacitor structures. ZrN_x/SiO₂/Si MOS capacitors exhibited n-type work function when the low-resistivity ZrN_x was deposited at low nitrogen gas flow. Further, variable work function by 0.6 eV was achieved by reactive sputter depositing TiN_x or ZrN_x at various nitrogen gas flow. Both metal-nitride systems demonstrate a shift in work function after RTP annealing, which is discussed in terms of Fermi level pinning due to extrinsic interface states. Still, the materials are promising in a gate last process as well as show potential as complementary gate electrodes.

The dielectric constant of as-deposited (Ta₂O₅)_1-x(TiO₂)_x thin films is around 22, whereas that of AlN is about 10. The latter is not dependent on the degree of crystallinity or on the measurement frequency up to 10 GHz. Both dielectrics exhibit characteristics appropriate for integrated capacitors. Finally, utilization of novel materials were demonstrated in strained SiGe surface-channel pMOSFETs with an ALD TiN/Al₂O₃ gate stack. The transistors were characterized with standard I-V, charge pumping, and low-frequency noise measurements. Correlation between the mobility and the oxide charge was found. Improved transistor performance was achieved by conducting low-temperature water vapor annealing, which reduced the negative charge in the Al₂O₃.