Effect of dc bias on the compositional ratio of WNX thin films prepared by rf-dc coupled magnetron sputtering

Migita, Tatsuo; Kamei, Ryuuzou; Tanaka, Takeshi; Kawabata, Ken‐ichi

doi:10.1016/s0169-4332(00)00683-8

Cited by 25 publications

(7 citation statements)

References 10 publications

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“…5(a μΩ-cm for T s = 700 °C. That is, the WN x layers in this study exhibit a range of resistivities from 1.1-4.5 ×10 -5 Ω-m, which is within the range of previously reported values for WN x of 0.1-5.0×10 -5 Ω-m [26,37,41,[64][65][66], while other reports on WN x layers including samples obtained by MOCVD or sputtering at high working gas pressures or high ion bombardment energies indicate even higher resistivities ranging from 10 -4 -10 -1 Ω-m [33,38,39,44,67,68], which is likely due to their lower crystalline quality. The layers grown at T s = 800 °C, which, as discussed above, consist primarily of BCC-W grains and have a low nitrogen concentration corresponding to x = 0.06, 0.06, and 0.04, respectively, have resistivities of 50±2, 42±1, and 48±2 μΩ-cm.…”

Section: Resultssupporting

confidence: 88%

Cubic β-WN layers: Growth and properties vs N-to-W ratio

Ozsdolay

Mulligan

Balasubramanian

et al. 2016

Surface and Coatings Technology

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Tungsten nitride layers, 1.45-μm-thick, were deposited by reactive magnetron sputtering on MgO(001), MgO(111), and Al 2 O 3 (0001) in 20 mTorr N 2 at T s = 500-800 °C. All layers deposited at T s = 500-700 °C form a cubic phase, as determined by X-ray diffraction ω-2θ scans, and show an N-to-W ratio x that decreases from x = 1.21 to 0.83 with increasing T s = 500-700 °C, as measured by energy dispersive and photoelectron spectroscopies. T s = 500 and 600 °C yields polycrystalline predominantly 111 oriented β-WN on all substrates. In contrast, deposition at 700 °C results in epitaxial growth of β-WN(111) and β-WN(001) on MgO(111) and MgO(001), respectively, and a 111-preferred orientation on Al 2 O 3 (0001). T s = 800 °C causes nitrogen loss and WN x layers with primarily BCC W grains and x = 0.04-0.06. Density functional theory calculations indicate an increase in structural stability by the introduction of either W or N vacancies into the cubic rock-salt structure, reducing the formation energy per atom from 0.32 eV for the rock-salt structure to 0.09 eV for WN 0.75 and -0.07 eV for WN 1.33 , to -0.42 eV for stoichiometric WN in the NbO structure. The out-of-plane lattice constant decreases from 4.357-4.169 Å with increasing T s = 500-700 °C. Comparing these values with calculated latticeconstants indicates that the W vacancy concentration increases from 6-11% for T s = 500-600 °C to 11-18% for T s = 700 °C, while the N vacancy concentration also increases from negligible to 18-29%. The simultaneous increase of both vacancy types is attributed to thermally activated N 2 recombination and desorption and atomic rearrangement towards the thermodynamically favorable cubic NbO structure which contains 25% of both W and N vacancies. The measured elastic modulus ranges from 110-260 GPa for 500-700 °C and decreases with increasing Ncontent, and increases to 350 GPa for T s = 800 °C. The room temperature resistivity decreases with increasing T s = 500-700 °C from 4.5-1.1×10 3 µΩ-cm, indicating a resistivity decrease with decreasing nitrogen content and increasing crystalline quality and phase purity.

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Section: Resultssupporting

confidence: 88%

Cubic β-WN layers: Growth and properties vs N-to-W ratio

Ozsdolay

Mulligan

Balasubramanian

et al. 2016

Surface and Coatings Technology

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“…Various deposition techniques have been studied for production of metal nitride thin films [12][13][14][15][16]. During the recent decades, the dense plasma focus (DPF) device [17,18] has been used for many applications such as generation of energetic ions, neutrons, X-rays and relativistic electrons [19] and deposition of thin films [20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Deposition of magnesium nitride thin films on stainless steel-304 substrates by using a plasma focus device

2014

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In this research, for the first time, we synthesize magnesium nitride thin films on 304-type stainless steel substrates using a Mather-type (2 kJ) plasma focus (PF) device. The films of magnesium nitride are coated with different number of focus shots (like 15, 25 and 35) at a distance of 8 cm from the anode tip and at 0°angular position with respect to the anode axis. For investigation of the structural properties and surface morphology of magnesium nitride films, we utilized the X-ray diffractometer (XRD), atomic force microscopy (AFM) and scanning electron microscopy (SEM) analysis, respectively. Also, the elemental composition is characterized by energy-dispersive X-ray (EDX) analysis. Furthermore, Vicker ' s microhardness is used to study the mechanical properties of the deposited films. The results show that the degree of crystallinity of deposited thin films (from XRD), the average size of particles and surface roughness (from AFM), crystalline growth of structures (from SEM) and the hardness values of the films depend on the number of focus shots. The EDX analysis demonstrates the existence of the elemental composition of magnesium in the deposited samples.

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“…For being widely used in optical and microelectronic applications, many researchers, such as Uekubo et al (1996), Park et al (1997) and Suh et al (1999), have extensively studied and characterized monolayer WNy coatings regarding crystal structure with respect to nitrogen content: Firstly, crystalline structure and nitrogen content of WNy are closely related to deposition conditions, such as nitrogen partial pressure, sputtering power (So et al, 1988), target dc bias voltage, and deposition and post-treating temperature (Volders et al, 2007), etc. For example, with target dc bias voltage varying from −100 to −500 V, Migita et al (2001) found that the sequential changes are achieved from the WN phase with (1 0 0) plane, W 2 N phase with (1 1 1) and (2 0 0) planes, and finally to the amorphous phase. Secondly, nitrogen content within WNy directly determines crystal structure of WNy.…”

Section: Resultsmentioning

confidence: 99%