Electron Cyclotron Resonance Nitrogen Plasma Research Articles

Deposition of TiN using tetrakis(dimethylamido)-titanium in an electron-cyclotron-resonance plasma process

High-quality TiN layers were deposited in an electron-cyclotron-resonance (ECR) plasma process at substrate temperatures between 350 and 600 °C. Tetrakis(dimethylamido)-titanium [Ti(NMe2)4] was used as precursor and introduced into the downstream region of an ECR nitrogen plasma. The electrical properties of the gold-colored TiN layers (45–100 μΩ cm) depend on the deposition rate, the substrate temperature, the microwave (MW) power, and the plasma gas composition. TiN with a resistivity of 45 μΩ cm could be obtained at a substrate temperature of 600 °C and a MW power of 400 W. The measured resistivities are so far the best reported values obtained by using a metalorganic precursor for TiN deposition. The deposits were characterized by resistivity measurements and electron probe microanalysis for chemical analysis. The morphology and step coverage was checked by atomic force and scanning electron microscopy.

Growth and characterization of thin SiN films grown on Si by electron cyclotron resonance nitrogen plasma treatment

Thin silicon nitride films have been fabricated on Si at a low substrate temperature (about 450 °C) by means of the direct exposure of Si wafers to an electron cyclotron resonance nitrogen plasma generated at 2.45 GHz. The film thickness can be controlled in the range 40–400 Å by suitably changing the nitrogen pressure, microwave power and substrate bias voltage. The activation energy characteristic of the growth is 0.42 ± 0.11 eV. The refractive indices of the films are 1.9–2.0 and the N-to-Si atomic ratio obtained by Rutherford backscattering spectrometry ranged from 1.35 to 1.43, indicating a nitrogen-rich film (stoichiometric value of 1.33). The average breakdown voltage of AlSiNSi capacitors is 11.9 ± 0.2 MV cm −1 and a typical leakage current density is about 10 −9 A cm −2 at a 2 V positive bias stressing for films 16 nm thick. Ion channelling experiments show that silicon nitride films form sharper interfaces (about 5 Å) on the Si substrate than chemically vapour-deposited nitrides do. Optical emission spectra measured during the film growth indicate that the nitrogen molecular ions are closely related to the growth rate and film quality.

Mössbauer spectra and structures of Fe/Fe-N multilayered films formed by Fe sputtering and ECR nitrogen plasma exposure

Fe/Fe-N multilayered films were prepared by an alternation of Fe sputtering and Electron Cyclotron Resonance (ECR) nitrogen plasma exposure, and the films were investigated by 57Fe Conversion Electron Mössbauer Spectroscopy (CEMS). ECR nitrogen plasma exposure of the sputtered Fe layers generated fine crystal ϵ-Fe2-3N and Fe2N grains, rather than thermally stable γ′-Fe4N. The Fe/Fe-N multilayered films has a periodic structure of [α-Fe]/[ϵ-Fe2-3N and Fe2N], and showed good soft magnetic properties.

Chemical and electrical characterization of AlGaAs/GaAs heterojunction bipolar transistors treated by electron cyclotron resonance plasmas

The effects of electron cyclotron resonance (ECR) hydrogen, nitrogen, and ammonia plasma have been studied by x-ray photoelectron spectroscopy. Experimental evidence shows that the ECR hydrogen plasma removes the native oxide on the GaAs surface and recovers the surface order. A mixed nitride-oxide surface layer is formed after nitrogen and ammonia plasma treatments. The appearance of the nitride layer correlates with the passivation of the GaAs surface and the much improved I-V characteristics of AlGaAs/GaAs heterojunction bipolar transistors.

Electron cyclotron resonance hydrogen and nitrogen plasma surface passivation of AlGaAs/GaAs heterojunction bipolar transistors

Electron cyclotron resonance (ECR) hydrogen (H) and nitrogen (N) plasma surface passivation on an AlGaAs/GaAs heterojunction bipolar transistor (HBT) is reported. As a result of the plasma processing, the base current ideality factor is improved from 2.67 to 1.96, and the maximum current gain is increased from 720 to 1000. In the low-current regime, the base current is reduced by two orders of magnitude. The nitride layer grown by nitrogen plasma passivates the GaAs surface and appears to be thermally stable without significant degradation. >