Influence of Al/TiN/SiO2 structure on MOS capacitor, Schottky diode, and fin field effect transistors devices

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Titanium nitride (TiN) films were tested for their suitability as upper electrodes in metal-oxide-semiconductor (MOS) capacitors and Schottky diodes and as metal gate electrodes in fin field effect transistor devices. TiOxNy formation on TiN surfaces was confirmed by x-ray photoelectron spectroscopy and appears to be associated with exposure of the metal electrodes to ambient air. In order to avoid the formation of TiOxNy and TiO2, a layer of aluminum (Al) was deposited in situ after the TiN deposition. TiN work function was calculated for the devices to study how dipole variation at the interface TiN/SiO2 influences TiN work function. TiOxNy and TiO2 formation at the film surface was found to affect the dipole variations at the TiN/SiO2 interface increasing the dipole influence on MOS structure. Furthermore, the estimated values TiN work function are suitable for complementary metal-oxide-semiconductor (CMOS) technology. Finally, this work had shown that Al/TiN structure can be used in CMOS technology, especially on n-type metal-oxide-semiconductor field effect transistor devices. (C) 2013 American Vacuum Society.315Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Oxygen incorporation and dipole variation in tantalum nitride film used as metal-gate electrode

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Tantalum nitride (TaN) films were used as gate electrodes in MOS capacitors fabricated with 8-nm-thick SiO2 as gate dielectric, and also used in Schottky diodes on n-type Si (100) substrates. TaN films with 20- and 100-nm-thick layers presented electrical resistivity of 439 and 472 mu Omega cm, respectively. XPS measurements on these TaN film surfaces show oxygen incorporation, which can be related to air exposure. MOS capacitors with TaN/SiO2/Si/Al and Al/TaN/SiO2/Si/Al structures, and Schottky diodes with TaN/Si/Al and Al/TaN/Si/Al structures, were fabricated on the same substrates. These devices were electrically characterized by capacitance-voltage (C-V) and current-voltage (I-V) measurements after sintering in a conventional furnace in a forming gas environment at 450 degrees C, for different times between 0 and 30 min. From C-V measurements of the MOS capacitors, the extracted TaN work function, effective charge densities, and flatband voltage values were found to be between 4.23 and 4.42 eV, -10(11) and -10(12) cm(-2), and -0.12 and 0.25 V, respectively. From I-V measurements of the Schottky diodes, work function and ideality factor values between 4.40 and 4.53 eV, and 1.0 and 1.9, respectively, were extracted. The variation of the TaN work function (extracted from C-V and I-V curves), flatband voltage, and ideality factor values were related to dipole variations (at the TaN/SiO2 interface), Ta and N vacancies in the TaN film, and oxygen incorporation on the TaN film surface. These results can contribute to work function engineering area for MOS technology. (C) 2012 American Vacuum Society. [http://dx.doi.org/10.1116/1.4729599]304Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES