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I Petrov - One of the best experts on this subject based on the ideXlab platform.
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low temperature ts tm 0 1 epitaxial growth of hfn mgo 001 via reactive hipims with metal ion synchronized Substrate Bias
Journal of Vacuum Science and Technology, 2018Co-Authors: Michelle Marie S Villamayor, Julien Keraudy, Tetsuhide Shimizu, Rommel Paulo B Viloan, Robert D Boyd, Daniel Lundin, J E Greene, I PetrovAbstract:Low-temperature epitaxial growth of refractory transition-metal nitride thin films by means of physical vapor deposition has been a recurring theme in advanced thin-film technology for several years. In the present study, 150-nm-thick epitaxial HfN layers are grown on MgO(001) by reactive high-power impulse magnetron sputtering (HiPIMS) with no external Substrate heating. Maximum film-growth temperatures Ts due to plasma heating range from 70 to 150 °C, corresponding to Ts/Tm = 0.10–0.12 (in which Tm is the HfN melting point in K). During HiPIMS, gas and sputtered metal-ion fluxes incident at the growing film surface are separated in time due to strong gas rarefaction and the transition to a metal-ion-dominated plasma. In the present experiments, a negative Bias of 100 V is applied to the Substrate, either continuously during the entire deposition or synchronized with the metal-rich portion of the ion flux. Two different sputtering-gas mixtures, Ar/N2 and Kr/N2, are employed in order to probe effects associated with the noble-gas mass and ionization potential. The combination of x-ray diffraction, high-resolution reciprocal-lattice maps, and high-resolution cross-sectional transmission electron microscopy analyses establishes that all HfN films have a cube-on-cube orientational relationship with the Substrate, i.e., [001]HfN||[001]MgO and (100)HfN||(100)MgO. Layers grown with a continuous Substrate Bias, in either Ar/N2 or Kr/N2, exhibit a relatively high mosaicity and a high concentration of trapped inert gas. In distinct contrast, layers grown in Kr/N2 with the Substrate Bias synchronized to the metal-ion-rich portion of HiPIMS pulses have much lower mosaicity, no measurable inert-gas incorporation, and a hardness of 25.7 GPa, in good agreement with the results for epitaxial HfN(001) layers grown at Ts = 650 °C (Ts/Tm = 0.26). The room-temperature film resistivity is 70 μΩ cm, which is 3.2–10 times lower than reported values for polycrystalline-HfN layers grown at Ts = 400 °C.
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low temperature ts tm 0 1 epitaxial growth of hfn mgo 001 via reactive hipims with metal ion synchronized Substrate Bias
Journal of Vacuum Science and Technology, 2018Co-Authors: Michelle Marie S Villamayor, Julien Keraudy, Tetsuhide Shimizu, Rommel Paulo B Viloan, Robert D Boyd, Daniel Lundin, J E Greene, I PetrovAbstract:Low-temperature epitaxial growth of refractory transition-metal nitride thin films by means of physical vapor deposition has been a recurring theme in advanced thin-film technology for several years. In the present study, 150-nm-thick epitaxial HfN layers are grown on MgO(001) by reactive high-power impulse magnetron sputtering (HiPIMS) with no external Substrate heating. Maximum film-growth temperatures Ts due to plasma heating range from 70 to 150 °C, corresponding to Ts/Tm = 0.10–0.12 (in which Tm is the HfN melting point in K). During HiPIMS, gas and sputtered metal-ion fluxes incident at the growing film surface are separated in time due to strong gas rarefaction and the transition to a metal-ion-dominated plasma. In the present experiments, a negative Bias of 100 V is applied to the Substrate, either continuously during the entire deposition or synchronized with the metal-rich portion of the ion flux. Two different sputtering-gas mixtures, Ar/N2 and Kr/N2, are employed in order to probe effects associated with the noble-gas mass and ionization potential. The combination of x-ray diffraction, high-resolution reciprocal-lattice maps, and high-resolution cross-sectional transmission electron microscopy analyses establishes that all HfN films have a cube-on-cube orientational relationship with the Substrate, i.e., [001]HfN||[001]MgO and (100)HfN||(100)MgO. Layers grown with a continuous Substrate Bias, in either Ar/N2 or Kr/N2, exhibit a relatively high mosaicity and a high concentration of trapped inert gas. In distinct contrast, layers grown in Kr/N2 with the Substrate Bias synchronized to the metal-ion-rich portion of HiPIMS pulses have much lower mosaicity, no measurable inert-gas incorporation, and a hardness of 25.7 GPa, in good agreement with the results for epitaxial HfN(001) layers grown at Ts = 650 °C (Ts/Tm = 0.26). The room-temperature film resistivity is 70 μΩ cm, which is 3.2–10 times lower than reported values for polycrystalline-HfN layers grown at Ts = 400 °C.Low-temperature epitaxial growth of refractory transition-metal nitride thin films by means of physical vapor deposition has been a recurring theme in advanced thin-film technology for several years. In the present study, 150-nm-thick epitaxial HfN layers are grown on MgO(001) by reactive high-power impulse magnetron sputtering (HiPIMS) with no external Substrate heating. Maximum film-growth temperatures Ts due to plasma heating range from 70 to 150 °C, corresponding to Ts/Tm = 0.10–0.12 (in which Tm is the HfN melting point in K). During HiPIMS, gas and sputtered metal-ion fluxes incident at the growing film surface are separated in time due to strong gas rarefaction and the transition to a metal-ion-dominated plasma. In the present experiments, a negative Bias of 100 V is applied to the Substrate, either continuously during the entire deposition or synchronized with the metal-rich portion of the ion flux. Two different sputtering-gas mixtures, Ar/N2 and Kr/N2, are employed in order to probe effects asso...
Jensue Chen - One of the best experts on this subject based on the ideXlab platform.
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effects of Substrate Bias and nitrogen flow ratio on the resistivity composition crystal structure and reflectance of reactively sputtered hafnium nitride film
Journal of Alloys and Compounds, 2009Co-Authors: Jiannshing Jeng, Chinhung Liu, Jensue ChenAbstract:Abstract Hf-N films were sputtered in an Ar + N 2 atmosphere, with different Substrate Biases (0 to −200 V) at various nitrogen flow ratios (N 2 % = 0–5%). The resistivity, composition, crystal structure, and reflectance of Hf-N films were examined. The resistivity of Hf-N films deposited at 0% nitrogen flow ratio decreases with increasing Substrate Bias. In addition, the resistivity of −200 V Biased Hf-N films increases to a limited extent with increasing nitrogen flow ratio, whereas the resistivity of zero- and −100 V Biased films increases abruptly with an increasing nitrogen flow ratio of up to 5%. The zero- and −100 V Biased Hf-N films display a hafnium oxide phase when film is deposited at a 5% N 2 flow ratio, while Hf-N films deposited at −200 V Bias show a HfN phase. The reflectance of zero- and −100 V Biased films deposited at 5% N 2 flow ratio shows a significant interference hump in the visible region. In addition, the reflectance edge of Hf-N films is related to the density of the conduction electron. The connection among resistivity, composition, crystal structure, and reflectance and how they are influenced by the Substrate Bias and nitrogen flow ratio is discussed.
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effects of Substrate Bias and nitrogen flow ratio on the resistivity and crystal structure of reactively sputtered zrnx films at elevated temperature
Journal of Vacuum Science and Technology, 2007Co-Authors: J S Jeng, S H Wang, Jensue ChenAbstract:ZrNx films were sputtered in an Ar+N2 atmosphere, with different Substrate Biases (zero to −200V) at a 2% nitrogen flow ratio and various nitrogen flow ratios (%N2=0.5%–24%) under −200V of Substrate Bias. The resistivity, crystal structure, and compositional depth profiles of ZrNx films, before and after vacuum annealing at 500–900°C, were investigated. At 2% N2, the resistivity of ZrNx films decreases with increasing Substrate Bias due to reduction of incorporated oxygen and porosity. Additionally, the resistivity of −200V Biased ZrNx films (%N2=2%) are about the same before and after annealing, but the resistivities of zero and −100V Biased ZrNx films increase with increasing annealing temperature. In addition, the ZrO2 phases (monoclinic and tetragonal) are found in ZrNx films deposited with 2% N2 and no Substrate Bias after annealing at 900°C; however, ZrN and tetragonal ZrO2 phases are revealed in ZrNx films sputtered with a Substrate Bias at the same temperature. On the other hand, the resistivities...
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effects of Substrate Bias on the reactive sputtered zr al n diffusion barrier films
Surface & Coatings Technology, 2005Co-Authors: Jian Long Ruan, Jowlay Huang, Jensue Chen, Ding Fwu LiiAbstract:Abstract Zirconium aluminum nitride (Zr–Al–N) diffusion barrier films were deposited on Si Substrates by DC-reactive magnetron sputtering under different Substrate Bias voltages. Cu films were subsequently sputtered onto the Zr–Al–N films without breaking vacuum. The effects of Substrate Bias voltage on the deposition rate, composition, microstructure, resistivity and diffusion barrier properties of Zr–Al–N films were investigated. Results indicated that the deposition rate and the contents of Al and O decreased with the increase of Substrate Bias voltages. The resputtering effect due to the high-energy ion bombardment on the film surface had significantly influenced the deposition rate and film's composition. With the increase of Substrate Bias voltage, the crystal orientation of films distributed more randomly. The Substrate Bias also decreased the resistivity and improved the diffusion barrier properties of films. The Biased Zr–Al–N films could effectively prevent diffusion of Cu to Si wafer even up to 800 °C for 30 min.
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effects of Substrate Bias and nitrogen flow ratio on the resistivity density stoichiometry and crystal structure of reactively sputtered zrnx thin films
Journal of Vacuum Science and Technology, 2004Co-Authors: S H Wang, Chingchun Chang, Jensue ChenAbstract:Thin films of ZrNx were prepared by reactive rf magnetron sputtering from a Zr target in an Ar+N2 atmosphere, with different Substrate Biases (zero to −200V) and nitrogen flow ratios (0.5%–24%). The resistivity, density, stoichiometry, and crystal structure of ZrNx films were investigated. With 2% of nitrogen flow ratio, all ZrNx films exhibit the cubic ZrN crystal phase, regardless of the magnitude of Substrate Bias. The zero-Biased ZrNx film contains substantial oxygen and shows high resistivity. Once a negative Bias is applied to the Substrate, the incorporated oxygen in ZrNx films can be reduced and the (111)ZrN preferred orientation is enhanced. Resistivity as low as 67μΩcm can be attained with −200V of Substrate Bias. At −200V of Substrate Bias, all films show the ZrN phase when the nitrogen flow ratio varies from 0.5% to 24%. However, the nitrogen content in ZrNx films increases continuously with the increasing nitrogen flow ratio. Resistivity of ZrNx films first decreases (0.5%–2%), and then incre...
Minoru Isshiki - One of the best experts on this subject based on the ideXlab platform.
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Influence of Substrate Bias Voltage on the Impurity Concentrations in Hf Films Deposited by Ion Beam Deposition Method
2020Co-Authors: Joon Woo Bae, Kouji Mimura, Jae-won Lim, Minoru IsshikiAbstract:Hf films have been deposited on Si(100) Substrate with or without a Substrate Bias voltage using a non-mass separated ion beam deposition (IBD) method. Secondary ion mass spectrometry (SIMS) and glow discharge mass spectrometry (GDMS) have been used to determine impurity concentrations of Hf films and a Hf target. By the SIMS results with Cs þ and O 2 þ ion beams, the Hf film deposited at V s ¼ 0 V contains more impurities than the Hf film deposited at V s ¼ À50 V. In addition, from GDMS results for the Hf target and the Hf films deposited at V s ¼ 0 and À50 V, almost all the impurities have reduced by applying a negative Substrate Bias voltage. It means that applying a negative Bias voltage to the Substrate can decrease the impurity concentrations in Hf films
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influence of Substrate Bias voltage on properties of pt thin films deposited by non mass separated ion beam deposition method
Materials Letters, 2009Co-Authors: Kouji Mimura, Masahito Uchikoshi, Mitsuhiro Wada, Makoto Ikeda, Minoru IsshikiAbstract:Abstract Pt thin films were deposited on Si Substrates by applying a negative Substrate Bias voltage using a non-mass separated ion beam deposition method. The effect of the Substrate Bias voltage on the properties of the deposited films was investigated. In the case of Pt thin films deposited without the Substrate Bias voltage, a columnar structure and small grains were observed. The electrical resistivity of the deposited Pt films was very high (49.3 ± 0.65 µΩ cm). By increasing the Substrate Bias voltage, no clear columnar structure was observed. At the Substrate Bias voltage of − 75 V, the resistivity of the Pt film showed a minimum value of 16.9 ± 0.2 µΩ cm closed to the value of bulk (10.6 µΩ cm).
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electrical resistivity of cu films deposited by ion beam deposition effects of grain size impurities and morphological defect
Journal of Applied Physics, 2006Co-Authors: J W Lim, Minoru IsshikiAbstract:Cu films deposited by ion beam deposition with or without a negative Substrate Bias voltage were found to have different states of dependence of electrical resistivity on film thickness. We have attempted to evaluate the effects of the film thickness, average grain size, impurities, and morphological defect on the resistivity increase of Cu films in addition to the surface scattering of the Fuch-Sondheimer model and the grain boundary scattering of the Mayadas-Shatzkes model. When the theoretical model was fit to the experimental data, the Cu films deposited at a Substrate Bias voltage of −50V showed that the electrical resistivity was in good agreement with the theoretical curve under the condition that the film thickness was 2.3 times larger than the average grain size and when p=0 and R=0.24. For the Cu films deposited without a Substrate Bias voltage, however, there was a slight deviation between the theoretical curve and the measured resistivity below a 100nm thickness, even at the condition of the f...
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effect of Substrate Bias voltage on the purity of cu films deposited by non mass separated ion beam deposition
Thin Solid Films, 2003Co-Authors: Kouji Mimura, Kiyoshi Miyake, M. Yamashita, Minoru IsshikiAbstract:Abstract Cu films were deposited on Si (1 0 0) Substrates at room temperature by a non-mass separated ion beam deposition method. The effect of the negative Substrate Bias voltage on the property of the Cu films was investigated by using field emission scanning electron microscopy and secondary ion mass spectroscopy. The Cu film deposited at the negative Bias voltage of −50 V showed an extremely fine and homogeneous morphology without a columnar structure. The purity of the Cu film deposited at the Bias voltage of −50 V was much improved in comparison with the 6N Cu target, while the Cu film deposited without applying Substrate Bias voltage contained more impurities than the 6N Cu target.
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effect of Substrate Bias voltage on the thermal stability of cu ta si structures deposited by ion beam deposition
Japanese Journal of Applied Physics, 2003Co-Authors: Jae-won Lim, Kouji Mimura, Kiyoshi Miyake, M. Yamashita, Minoru IsshikiAbstract:The interfacial reactions of the Cu (100 nm)/Ta (50 nm)/Si structures and their relationship with the microstructure of Ta diffusion barrier are investigated. Ta films were deposited on Si (100) Substrates using a non-mass separated ion beam deposition system at various Bias voltages ranging from 0 to -200 V. An optimum applied Substrate Bias voltage of -125 V was found to yield a dominant α-Ta film with a noncolumnar structure, low electrical resistivity (about 40 µΩcm) and smooth surface. A Ta diffusion barrier which was deposited at the optimum Bias voltage prevented Cu–Si interaction up to 600°C for 60 min in flowing purified H2, whereas a Ta layer with a columnar structure, deposited at zero Bias voltage, degraded at 300°C. Two different reactions of the Cu/Ta (0 V)/Si and the Cu/Ta (-125 V)/Si structures concerning the thermal stability were investigated and discussed on the basis of the experimental results.
J E Greene - One of the best experts on this subject based on the ideXlab platform.
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low temperature ts tm 0 1 epitaxial growth of hfn mgo 001 via reactive hipims with metal ion synchronized Substrate Bias
Journal of Vacuum Science and Technology, 2018Co-Authors: Michelle Marie S Villamayor, Julien Keraudy, Tetsuhide Shimizu, Rommel Paulo B Viloan, Robert D Boyd, Daniel Lundin, J E Greene, I PetrovAbstract:Low-temperature epitaxial growth of refractory transition-metal nitride thin films by means of physical vapor deposition has been a recurring theme in advanced thin-film technology for several years. In the present study, 150-nm-thick epitaxial HfN layers are grown on MgO(001) by reactive high-power impulse magnetron sputtering (HiPIMS) with no external Substrate heating. Maximum film-growth temperatures Ts due to plasma heating range from 70 to 150 °C, corresponding to Ts/Tm = 0.10–0.12 (in which Tm is the HfN melting point in K). During HiPIMS, gas and sputtered metal-ion fluxes incident at the growing film surface are separated in time due to strong gas rarefaction and the transition to a metal-ion-dominated plasma. In the present experiments, a negative Bias of 100 V is applied to the Substrate, either continuously during the entire deposition or synchronized with the metal-rich portion of the ion flux. Two different sputtering-gas mixtures, Ar/N2 and Kr/N2, are employed in order to probe effects associated with the noble-gas mass and ionization potential. The combination of x-ray diffraction, high-resolution reciprocal-lattice maps, and high-resolution cross-sectional transmission electron microscopy analyses establishes that all HfN films have a cube-on-cube orientational relationship with the Substrate, i.e., [001]HfN||[001]MgO and (100)HfN||(100)MgO. Layers grown with a continuous Substrate Bias, in either Ar/N2 or Kr/N2, exhibit a relatively high mosaicity and a high concentration of trapped inert gas. In distinct contrast, layers grown in Kr/N2 with the Substrate Bias synchronized to the metal-ion-rich portion of HiPIMS pulses have much lower mosaicity, no measurable inert-gas incorporation, and a hardness of 25.7 GPa, in good agreement with the results for epitaxial HfN(001) layers grown at Ts = 650 °C (Ts/Tm = 0.26). The room-temperature film resistivity is 70 μΩ cm, which is 3.2–10 times lower than reported values for polycrystalline-HfN layers grown at Ts = 400 °C.
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low temperature ts tm 0 1 epitaxial growth of hfn mgo 001 via reactive hipims with metal ion synchronized Substrate Bias
Journal of Vacuum Science and Technology, 2018Co-Authors: Michelle Marie S Villamayor, Julien Keraudy, Tetsuhide Shimizu, Rommel Paulo B Viloan, Robert D Boyd, Daniel Lundin, J E Greene, I PetrovAbstract:Low-temperature epitaxial growth of refractory transition-metal nitride thin films by means of physical vapor deposition has been a recurring theme in advanced thin-film technology for several years. In the present study, 150-nm-thick epitaxial HfN layers are grown on MgO(001) by reactive high-power impulse magnetron sputtering (HiPIMS) with no external Substrate heating. Maximum film-growth temperatures Ts due to plasma heating range from 70 to 150 °C, corresponding to Ts/Tm = 0.10–0.12 (in which Tm is the HfN melting point in K). During HiPIMS, gas and sputtered metal-ion fluxes incident at the growing film surface are separated in time due to strong gas rarefaction and the transition to a metal-ion-dominated plasma. In the present experiments, a negative Bias of 100 V is applied to the Substrate, either continuously during the entire deposition or synchronized with the metal-rich portion of the ion flux. Two different sputtering-gas mixtures, Ar/N2 and Kr/N2, are employed in order to probe effects associated with the noble-gas mass and ionization potential. The combination of x-ray diffraction, high-resolution reciprocal-lattice maps, and high-resolution cross-sectional transmission electron microscopy analyses establishes that all HfN films have a cube-on-cube orientational relationship with the Substrate, i.e., [001]HfN||[001]MgO and (100)HfN||(100)MgO. Layers grown with a continuous Substrate Bias, in either Ar/N2 or Kr/N2, exhibit a relatively high mosaicity and a high concentration of trapped inert gas. In distinct contrast, layers grown in Kr/N2 with the Substrate Bias synchronized to the metal-ion-rich portion of HiPIMS pulses have much lower mosaicity, no measurable inert-gas incorporation, and a hardness of 25.7 GPa, in good agreement with the results for epitaxial HfN(001) layers grown at Ts = 650 °C (Ts/Tm = 0.26). The room-temperature film resistivity is 70 μΩ cm, which is 3.2–10 times lower than reported values for polycrystalline-HfN layers grown at Ts = 400 °C.Low-temperature epitaxial growth of refractory transition-metal nitride thin films by means of physical vapor deposition has been a recurring theme in advanced thin-film technology for several years. In the present study, 150-nm-thick epitaxial HfN layers are grown on MgO(001) by reactive high-power impulse magnetron sputtering (HiPIMS) with no external Substrate heating. Maximum film-growth temperatures Ts due to plasma heating range from 70 to 150 °C, corresponding to Ts/Tm = 0.10–0.12 (in which Tm is the HfN melting point in K). During HiPIMS, gas and sputtered metal-ion fluxes incident at the growing film surface are separated in time due to strong gas rarefaction and the transition to a metal-ion-dominated plasma. In the present experiments, a negative Bias of 100 V is applied to the Substrate, either continuously during the entire deposition or synchronized with the metal-rich portion of the ion flux. Two different sputtering-gas mixtures, Ar/N2 and Kr/N2, are employed in order to probe effects asso...
Helmersson Ulf - One of the best experts on this subject based on the ideXlab platform.
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Low temperature growth of stress-free single phase alpha-W films using HiPIMS with synchronized pulsed Substrate Bias
'AIP Publishing', 2021Co-Authors: Shimizu Tetsuhide, Takahashi Kazuki, Boyd Robert, Viloan, Rommel Paulo, Keraudy Julien, Lundin Daniel, Yang Ming, Helmersson UlfAbstract:Efficient metal-ion-irradiation during film growth with the concurrent reduction of gas-ion-irradiation is realized for high power impulse magnetron sputtering by the use of a synchronized, but delayed, pulsed Substrate Bias. In this way, the growth of stress-free, single phase alpha -W thin films is demonstrated without additional Substrate heating or post-annealing. By synchronizing the pulsed Substrate Bias to the metal-ion rich portion of the discharge, tungsten films with a 110 oriented crystal texture are obtained as compared to the 111 orientation obtained using a continuous Substrate Bias. At the same time, a reduction of Ar incorporation in the films are observed, resulting in the decrease of compressive film stress from sigma =1.80-1.43GPa when switching from continuous to synchronized Bias. This trend is further enhanced by the increase of the synchronized Bias voltage, whereby a much lower compressive stress sigma =0.71GPa is obtained at U-s=200V. In addition, switching the inert gas from Ar to Kr has led to fully relaxed, low tensile stress (0.03GPa) tungsten films with no measurable concentration of trapped gas atoms. Room-temperature electrical resistivity is correlated with the microstructural properties, showing lower resistivities for higher U-s and having the lowest resistivity (14.2 mu Omega cm) for the Kr sputtered tungsten films. These results illustrate the clear benefit of utilizing selective metal-ion-irradiation during film growth as an effective pathway to minimize the compressive stress induced by high-energetic gas ions/neutrals during low temperature growth of high melting temperature materials.Funding Agencies|Swedish Research CouncilSwedish Research CouncilEuropean Commission [VR 2018-04139]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009-00971]; Japan Society for the Promotion of Science (JSPS)Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT)Japan Society for the Promotion of Science [17KK0136]
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Low temperature (Ts/Tm < 0.1) epitaxial growth of HfN/MgO(001) via reactive HiPIMS with metal-ion synchronized Substrate Bias
2018Co-Authors: Villamayor, Michelle Marie S., Shimizu Tetsuhide, Boyd Robert, Keraudy Julien, Lundin Daniel, Viloan, Rommel Paulo B., Greene J. E., Petrova Ivan, Helmersson UlfAbstract:Low-temperature epitaxial growth of refractory transition-metal nitride thin films by means of physical vapor deposition has been a recurring theme in advanced thin-film technology for several years. In the present study, 150-nm-thick epitaxial HfN layers are grown on MgO(001) by reactive high-impulse magnetron sputtering (HiPIMS) with no external Substrate heating. Maximum film growth temperatures Ts due to plasma heating range from 70-150 {\deg}C, corresponding to Ts/Tm = 0.10-0.12 (in which Tm is the HfN melting point in K). During HiPIMS, gas and sputtered-metal ion fluxes incident at the growing film surface are separated in time due to strong gas rarefaction and the transition to a metal-ion dominated plasma. In the present experiments, a negative Bias of 100 V is applied to the Substrate, either continuously during the entire deposition or synchronized with the metal-rich portion of the ion flux. Two different sputtering-gas mixtures, Ar/N2 and Kr/N2, are employed in order to probe effects associated with the noble-gas mass and ionization potential. The combination of x-ray diffraction, high-resolution reciprocal-lattice maps, and high-resolution cross-sectional transmission electron microscopy analyses establish that all HfN films have a cube-on-cube orientational relationship with the Substrate, i.e., [001]HfN||[001]MgO and (100)HfN||(100)MgO. Layers grown with continuous Substrate Bias, in either Ar/N2 or Kr/N2, exhibit a relatively high mosaicity and a high concentration of trapped inert gas. In distinct contrast, layers grown in Kr/N2 with the Substrate Bias synchronized to the metal-ion-rich portion of HiPIMS pulses, have much lower mosaicity, no measurable inert-gas incorporation, and a hardness of 25.7 GPa, in good agreement with results for epitaxial HfN(001) layers grown at Ts = 650 C (Ts/Tm = 0.26)
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Low temperature (T-s/T-m < 0.1) epitaxial growth of HfN/MgO(001) via reactive HiPIMS with metal-ion synchronized Substrate Bias
'American Vacuum Society', 2018Co-Authors: Villamayor, Michelle M, Shimizu Tetsuhide, Boyd Robert, Viloan, Rommel Paulo, Keraudy Julien, Lundin Daniel, Greene J. E., Petrov Ivan, Helmersson UlfAbstract:Low-temperature epitaxial growth of refractory transition-metal nitride thin films by means of physical vapor deposition has been a recurring theme in advanced thin-film technology for several years. In the present study, 150-nm-thick epitaxial HfN layers are grown on MgO(001) by reactive high-power impulse magnetron sputtering (HiPIMS) with no external Substrate heating. Maximum film-growth temperatures T-s due to plasma heating range from 70 to 150 degrees C, corresponding to T-s/T-m = 0.10-0.12 (in which T-m is the HfN melting point in K). During HiPIMS, gas and sputtered metal-ion fluxes incident at the growing film surface are separated in time due to strong gas rarefaction and the transition to a metal-ion-dominated plasma. In the present experiments, a negative Bias of 100 V is applied to the Substrate, either continuously during the entire deposition or synchronized with the metal-rich portion of the ion flux. Two different sputtering-gas mixtures, Ar/N-2 and Kr/N-2, are employed in order to probe effects associated with the noble-gas mass and ionization potential. The combination of x-ray diffraction, high-resolution reciprocal-lattice maps, and high-resolution cross-sectional transmission electron microscopy analyses establishes that all HfN films have a cube-on-cube orientational relationship with the Substrate, i.e., [001](HfN)parallel to[001](MgO) and (100)(HfN)parallel to(100)(MgO). Layers grown with a continuous Substrate Bias, in either Ar/N-2 or Kr/N-2, exhibit a relatively high mosaicity and a high concentration of trapped inert gas. In distinct contrast, layers grown in Kr/N-2 with the Substrate Bias synchronized to the metal-ion-rich portion of HiPIMS pulses have much lower mosaicity, no measurable inert-gas incorporation, and a hardness of 25.7 GPa, in good agreement with the results for epitaxial HfN(001) layers grown at T-s = 650 degrees C (T-s/T-m = 0.26). The room-temperature film resistivity is 70 mu Omega cm, which is 3.2-10 times lower than reported values for polycrystalline-HfN layers grown at T-s = 400 degrees C. (c) 2018 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).Funding Agencies|Swedish Research Council [VR 621-2014-4882]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009-00971]
