Stress, Microstructure and Temperature Stability of Reactive Sputter Deposited WNx Thin Films

2000 ◽  
Vol 612 ◽  
Author(s):  
K. D. Leedy ◽  
M. J. O'Keefe ◽  
J. G. Wilson ◽  
R. Osterday ◽  
J. T. Grant

AbstractTungsten nitride (WNx) thin films can be used as Schottky barriers in high power, high temperature semiconductor devices or as diffusion barriers between Cu, low-k dielectric and silicon because each application requires a thermally stable film. Therefore, it is important to understand the thin film properties of WNx as a function of deposition conditions and elevated temperature exposure. In this investigation, the influence of nitrogen content and post deposition annealing on the stress and microstructure of reactive dc magnetron sputter deposited WNx films was analyzed. With an increasing N2 to Ar flow ratio, the as-deposited crystal structure of the films changed from α-W to β-W to amorphous WNx and finally to W2N. Rapid thermal anneals up to 650°C resulted in large tensile stress increases and phase transformations to W2N in the nitrogen-containing films. Grain growth during annealing decreased as the concentration of nitrogen in the film increased. The nitrogen content in the films was determined using x-ray photoelectron spectroscopy (XPS).

1999 ◽  
Vol 594 ◽  
Author(s):  
K. D. Leedy ◽  
M. J. O'Keefe ◽  
J. T. Grant

AbstractInterest in tantalum nitride thin films for use as diffusion barriers in Cu-based microelectronic interconnects merits the study of tantalum nitride thin film properties as a function of deposition conditions and elevated temperature exposure. In this investigation, the influence of nitrogen content and post deposition annealing on the stress, microstructure and resistivity of Ta(N) films was analyzed. Ta(N) thin films were deposited by reactive dc magnetron sputtering of a Ta target in Ar/N2 gas mixtures. With an increasing N2 to Ar flow ratio, the as-deposited crystal structure of the films changed from ß-Ta to bcc Ta with N in solid solution to TaN0.1 to Ta2N and finally to TaN. The as-deposited Ta(N) stress, grain size and resistivity of the films were found to be strongly dependent on the phase(s) present. Films with less than 20 at. % nitrogen concentration displayed large compressive stress increases during 650°C anneals in flowing N2. Phase transformations to Ta2N occurred after 650°C anneals in films with nitrogen concentrations from ∼ 15 to 25 at. %. Microstructural characterization using transmission electron microscopy and x-ray diffraction, and chemical analysis by x-ray photoelectron spectroscopy and Auger electron spectroscopy of the Ta(N) films were used to identify the as-deposited and transformed phases.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Haijun Wu ◽  
Shoucong Ning ◽  
Moaz Waqar ◽  
Huajun Liu ◽  
Yang Zhang ◽  
...  

AbstractTraditional strategies for improving piezoelectric properties have focused on phase boundary engineering through complex chemical alloying and phase control. Although they have been successfully employed in bulk materials, they have not been effective in thin films due to the severe deterioration in epitaxy, which is critical to film properties. Contending with the opposing effects of alloying and epitaxy in thin films has been a long-standing issue. Herein we demonstrate a new strategy in alkali niobate epitaxial films, utilizing alkali vacancies without alloying to form nanopillars enclosed with out-of-phase boundaries that can give rise to a giant electromechanical response. Both atomically resolved polarization mapping and phase field simulations show that the boundaries are strained and charged, manifesting as head-head and tail-tail polarization bound charges. Such charged boundaries produce a giant local depolarization field, which facilitates a steady polarization rotation between the matrix and nanopillars. The local elastic strain and charge manipulation at out-of-phase boundaries, demonstrated here, can be used as an effective pathway to obtain large electromechanical response with good temperature stability in similar perovskite oxides.


2001 ◽  
Vol 670 ◽  
Author(s):  
Akira Nishiyama ◽  
Akio Kaneko ◽  
Masato Koyama ◽  
Yoshiki Kamata ◽  
Ikuo Fujiwara ◽  
...  

ABSTRACTTi-Si-O films were sputter deposited from TiO2+SiO2 composite targets with various SiO2 content. The phase separation occurred for every SiO2 content used in this experiment (from 14% to 75%) and it has been revealed that nanocrystalline (TiO2)1-x(SiO2)x films in which anatase TiO2 forms tiny grains were obtained when x in the film is larger than 0.26. The tiny grain was effective for suppressing the thermal grooving phenomenon of the thin films by the post deposition annealing which leads to the leakage current increase. The dielectric constant of the nanocrystalline film was varied with the SiO2 content from the value of the bulk anatase to SiO2.


Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2284
Author(s):  
Y. K. Sa ◽  
Junghwan Bang ◽  
Junhyuk Son ◽  
Dong-Yurl Yu ◽  
Yun-Chan Kim

This paper reported the enhancement in thermo-mechanical properties and chemical stability of porous SiCOH dielectric thin films fabricated with molecularly scaled pores of uniform size and distribution. The resulting porous dielectric thin films were found to exhibit far stronger resistance to thermo-mechanical instability mechanisms common to conventional SiCOH dielectric thin films without forgoing an ultralow dielectric constant (i.e., ultralow-k). Specifically, the elastic modulus measured by nano-indentation was 13 GPa, which was substantially higher than the value of 6 GPa for a porous low-k film deposited by a conventional method, while dielectric constant exhibited an identical value of 2.1. They also showed excellent resistance against viscoplastic deformation, as measured by the ball indentation method, which represented the degree of chemical degradation of the internal bonds. Indentation depth was measured at 5 nm after a 4-h indentation test at 400 °C, which indicated an ~89% decrease compared with conventional SiCOH film. Evolution of film shrinkage and dielectric constant after annealing and plasma exposure were reduced in the low-k film with a self-organized molecular film. Analysis of the film structure via Fourier-transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) indicated an increase in symmetric linear Si–O–Si molecular chains with terminal –CH3 bonds that were believed to be responsible for both the decrease in dipole moment/dielectric constant and the formation of molecular scaled pores. The observed enhanced mechanical and chemical properties were also attributed to this unique nano-porous structure.


2018 ◽  
Vol 24 (8) ◽  
pp. 5872-5876
Author(s):  
G Balakrishnan ◽  
V Sathiyaraj ◽  
M Dinesh ◽  
P. Naveen Chandran ◽  
C Thamotharan

In the present work, nanostructured tungsten nitride (WN) thin films were deposited by RF reactive magnetron sputtering technique in a mixture of N2 and Argon atmosphere and its microstructure and mechanical properties were investigated. The Argon pressure was kept constant at 20 sccm, while the N2 partial pressures were varied (3%, 5%, 10% and 15%). The WN thin films are deposited on SS304 stainless steel substrates at a temperature of 500 °C. The microstructural property was analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM) and mechanical properties were evaluated by nanoindentation technique. The XRD studies indicated the formation of different phases as a function of nitrogen content. The hardness and the young’s modulus values were in the range 27–39 GPa and 239–280 GPa, respectively. The high hardness values correspond to the coatings with the low nitrogen content and vice-versa. The mechanical properties of the tungsten nitride coatings were strongly influenced by the microstructure.


2002 ◽  
Vol 750 ◽  
Author(s):  
Yuka Nasu ◽  
Masami Aono ◽  
Shinichiro Aizawa ◽  
Nobuaki Kitazawa ◽  
Yoshihisa Watanabe

ABSTRACTCarbon nitride (CNx) thin films have been prepared by hot carbon filament chemical vapor deposition, and the nitrogen content in the films is approximately 0.05. The CNx films have been irradiated by 0.1 keV nitrogen ions to increase the nitrogen content after deposition. The nitrogen content in the CNx films was obtained with X-ray photoelectron spectroscopy. Scanning electron microscopy was employed to study microstructures of the films. The experimental results show that nitrogen ions are chemically combined with the CNx films and as a result the nitrogen content increases up to approximately 0.30. Furthermore, it is found that nitrogen ions change the film microstructures and sputter the surfaces of CNx films.


2019 ◽  
Vol 22 ◽  
pp. 65-73
Author(s):  
Ørnulf Nordseth ◽  
Irinela Chilibon ◽  
Bengt Gunnar Svensson ◽  
Raj Kumar ◽  
Sean Erik Foss ◽  
...  

Cuprous oxide (Cu2O) has a high optical absorption coefficient and favourable electrical properties, which make Cu2O thin films attractive for photovoltaic applications. Using reactive radio-frequency magnetron sputtering, high quality Cu2O thin films with good carrier transport properties were prepared. This paper presents the characteristics of Cu2O thin films that were sputter deposited on quartz substrates and subjected to post-deposition rapid thermal annealing. The thickness of the thin films and the optical constants were determined by ellipsometry spectroscopy (SE). The optical transmittance increased in lower wavelength region after annealing at 900 ̊C in rapid thermal annealing (RTA). The structural and morphological properties of the Cu2O thin films were investigated by electronic scanning microscopy (SEM) and atomic force microscopy (AFM), whereas elemental analysis was performed by X-ray fluorescence spectroscopy (XRF). The carrier mobility, carrier density and film resistivity were changed after post-deposition rapid thermal annealing from respectively ~14 cm2/Vs, ~2.3 x 1015 cm-3 and ~193 Ωcm for the as-deposited Cu2O film to ~49 cm2/Vs, ~5.0 x 1014 cm-3 and ~218 Ωcm for the annealed Cu2O film. The investigation suggests that the sputter-deposited Cu2O thin films have good potential for application as absorber layers in solar cells.


2005 ◽  
Vol 12 (04) ◽  
pp. 587-595 ◽  
Author(s):  
M. RUSOP ◽  
T. SOGA ◽  
T. JIMBO ◽  
M. UMENO ◽  
M. SHARON

Amorphous carbon nitride ( a-CN x) films have been deposited by pulsed laser deposition at 0.8 Torr nitrogen gas ambient with varying substrate temperature from 20 to 500°C. The effects of the substrate temperature and ambient nitrogen gas pressure on the surface morphology, composition, nitrogen content, structure, and electrical properties of the a-CN x thin films have been investigated. The deposited a-CN x films were characterized by X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, Fourier transform infrared (FTIR), scanning electron microscopy (SEM), atomic force microscopy (AFM), UV-Visible transmittance, and four-probe resistance measurement. It is found that the amorphous structure of a-CN x films can be changed by the substrate temperature (ST) and the a-CN x films with high nitrogen content have relatively high electrical resistivity. Also, graphitization is found to cause the reduction of nitrogen content and changes in the bonding structure of nitrogen atoms in the films.


Sensors ◽  
2019 ◽  
Vol 19 (6) ◽  
pp. 1320 ◽  
Author(s):  
Mohamed Abdel-Rahman ◽  
Muhammad Zia ◽  
Mohammad Alduraibi

In this study, vanadium oxide (VxOy) semiconducting resistive thermometer thin films were developed, and their temperature-dependent resistive behavior was examined. Multilayers of 5-nm-thick vanadium pentoxide (V2O5) and 5-nm-thick vanadium (V) films were alternately sputter-deposited, at room temperature, to form 105-nm-thick VxOy films, which were post-deposition annealed at 300 °C in O2 and N2 atmospheres for 30 and 40 min. The synthesized VxOy thin films were then patterned into resistive thermometer structures, and their resistance versus temperature (R-T) characteristics were measured. Samples annealed in O2 achieved temperature coefficients of resistance (TCRs) of −3.0036 and −2.4964%/K at resistivity values of 0.01477 and 0.00819 Ω·cm, respectively. Samples annealed in N2 achieved TCRs of −3.18 and −1.1181%/K at resistivity values of 0.04718 and 0.002527 Ω·cm, respectively. The developed thermometer thin films had TCR/resistivity properties suitable for microbolometer and antenna-coupled microbolometer applications. The employed multilayer synthesis technique was shown to be effective in tuning the TCR/resistivity properties of the thin films by varying the annealing conditions.


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