Intrinsic reoxidation of microwave plasma-nitrided gate dielectrics

Alshareef, Husam N.; Niimi, H.; Varghese, A.; Bevan, M. J.; Kuan, R.; Holt, Jennifer; Tiner, P.; Khamankar, R.

doi:10.1063/1.1895486

Cited by 5 publications

(3 citation statements)

References 7 publications

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“…Indeed a number of candidate NMOS and PMOS metals have recently appeared. For NMOS, TaC x (4.2 eV) and TaTb x N (4.23 eV) appear promising [240,241], while for PMOS Ru (5.03 eV) and (Ta,Al)N with WF of 5.0 eV are suitable [242,243].…”

Section: Effective Work Functionsmentioning

confidence: 99%

High dielectric constant gate oxides for metal oxide Si transistors

2005

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The scaling of complementary metal oxide semiconductor transistors has led to the silicon dioxide layer, used as a gate dielectric, being so thin (1.4 nm) that its leakage current is too large. It is necessary to replace the SiO 2 with a physically thicker layer of oxides of higher dielectric constant (κ) or 'high K' gate oxides such as hafnium oxide and hafnium silicate. These oxides had not been extensively studied like SiO 2 , and they were found to have inferior properties compared with SiO 2 , such as a tendency to crystallize and a high density of electronic defects. Intensive research was needed to develop these oxides as high quality electronic materials. This review covers both scientific and technological issuesthe choice of oxides, their deposition, their structural and metallurgical behaviour, atomic diffusion, interface structure and reactions, their electronic structure, bonding, band offsets, electronic defects, charge trapping and conduction mechanisms, mobility degradation and flat band voltage shifts. The oxygen vacancy is the dominant electron trap. It is turning out that the oxides must be implemented in conjunction with metal gate electrodes, the development of which is further behind. Issues about work function control in metal gate electrodes are discussed.

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Section: Effective Work Functionsmentioning

confidence: 99%

High dielectric constant gate oxides for metal oxide Si transistors

2005

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“…The incorporation of nitrogen has been extensively studied in gate dielectric films including SiO 2 and various high-k films because it plays a key role in present and near-future metaloxide-semiconductor devices. [4][5][6] Although N incorporation is a very promising process for control of interfacial reactions and enhancement of thermal stability of the film, the amount of nitrogen incorporated in HfO 2 is not stably maintained, which critically affects electrical device features. 4,7 Among the electrical device features, the most important characteristics in leakage and reliability of the gate dielectric are basically dependent on the band gap of the film and on band alignment with the Si substrate.…”

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confidence: 99%

Change in band alignment of HfO2 films with annealing treatments

Yim

Jang

et al. 2008

Applied Physics Letters

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Energy band alignment of a nitrided HfO2 film and dependence of the band gap (Eg) on annealing treatments with nitrogen plasma and ambient gases (N2 and O2) were studied by reflection electron energy loss spectra and x-ray photoelectron spectroscopy. We also investigated the nitrogen content in the film and its influence on the band alignment using medium energy ion scattering. The nitrogen incorporated into the HfO2 film by directed nitrogen plasma treatment significantly decreased the band gap and band offsets, i.e., the incorporated N in the film decreased both conduction and valance band offsets. The nitrogen content in depth direction was dependent on the postannealing conditions using O2 or N2.

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“…It has been reported that the change in the nitrogen content of SiON gate dielectrics processed at high plasma pressure impacts gate leakage current, but not EOT. 12 The electrical performance in Fig. 8 can be explained by the nitrogen profile (inset) and by the way in which residual oxygen atoms and radicals behave during the nitridation process.…”

Section: Plasma Nitridation Optimizationmentioning

confidence: 99%