Study of ZrO2/TiN High-K/Metal Gate Stacks

With the development of the semiconductor industry, the feature size of the transistors continues shrinking .The traditional SiO2 gate oxide does not fulfill the requirement of technology node. Therefore, the high-k materials was substituted for the conventional SiO2 as the gate dielectric of metal-oxide-semiconductor (MOS) devices. In this thesis, ultrathin ZrO2 dioxide was deposited by atomic layer deposition (ALD) and the argon plasma treatment was used to tailor the electrical properties of the ZrO2 gate dielectric. Moreover, in recent years, it has been reported that TiN is capable of being used as metal gate in MOSFET. Thus, a layer of TiN was deposited by ALD on the ZrO2 gate dielectric as the metal and the electrical characteristics of the MOS device were investigated. Besides, for high performance MOS transistor, the effective work function of metal gate is expected to be close to the conduction band (4.1eV) or valence band (5.2eV) of the silicon. Thus the effective work function of TiN was also modulated and measured in this study.