AVS 52nd International Symposium
    Plasma Science and Technology Wednesday Sessions
       Session PS+TF-WeM

Paper PS+TF-WeM10
Characteristics of HfN deposited by using Remote Plasma Enhanced Atomic Layer Deposition Method

Wednesday, November 2, 2005, 11:20 am, Room 302

Session: Plasma Enhanced CVD and ALD
Presenter: K.W. Lee, Hanyang University, Korea
Authors: K.W. Lee, Hanyang University, Korea
S.J. Han, Hanyang University, Korea
G.J. Kim, Hanyang University, Korea
W.H. Jeong, Hanyang University, Korea
H.T. Jeon, Hanyang University, Korea
Correspondent: Click to Email
Metal oxide films with high dielectric constants (high-k) have been studied recently to overcome the current disadvantages of SiO@sub2@ material. This high-k oxide material also need to apply new gate electrode because of the problems of polysilicon/high-k gate stacks such as poly-Si depletion effect, Fermi level pinning, surface phonon scattering, high threshold voltages and channel mobility degradation in real devices. Current polysilicon as a gate electrode results in poor transistor performance. Due to these problems new metal gate materials are needed to solve these problems because the metal/high-k gate stack is very effective in screening the phonon scattering and improves the channel mobility. And the use of metal gate electrode eliminates poly-Si depletion effect and Fermi level pinning. Among the many candidates the refractory metal nitrides such as titanium nitride (TiN) and tantalum nitride (TaN) are considered as the solutions to replace current poly-Si gate electrode. HfN exhibits various advantages such as thermal stability, midgap work function(4.65eV), and low lattice mismatch(1.13) with HfO@sub2@ gate dielectric and is considered as one of the most suitable candidates as gate electrode. In this work we studied this HfN material with remote plasma enhanced atomic layer deposition(RPEALD) method with tetrakis-ethylmethylamino-hafnium (TEMAH), Hf[N(CH@sub3@)C@sub2@H@sub5@]@sub4@ as a Hf precursor and NH@sub3@ plasma as a reactant gas. This HfN gate electrode was deposited on the HfO@sub2@ gate oxide. After deposition, the physical and chemical characteristics were evaluated, and MOS capacitors were fabricated with the HfN electrode to measure the electrical properties. The interfacial layers of deposited the HfN/HfO@sub2@ and the TiN/HfO@sub2@ stacks were investigated by high resolution transmission electron microscope (HRTEM).