摘要:

The design and performance of magnetron sources which provide at the substrate not only the flux of sputtered atoms but also fluxes of electrons and ions from the plasma are described. This energetic particle bombardment (which is directed to the substrate by an unbalanced magnetic field design) can be beneficial, as when it is used to ion assist the growth of the depositing thin film, or deleterious, e.g., by providing extra heating. Applications of unbalanced magnetrons to investigate the technology of magnetron sputtering are described. Ion assistance of the growing film increases the biaxial compressive stress in the growing film due to an atomic peening process. The lattice strain produced by the stress can be measured using x‐ray diffraction, and can be used to quantify the degree of ion assistance. Effects studied in films of refractory metals include the increase in stress until plastic flow occurs during growth, changes in preferential orientation, the effectiveness of the different gases Ar and Xe in producing stress, energetic neutral bombardment, and moderation of sputtered atoms. New results are presented here for the temperature dependence of the stress production in molybdenum films. The application of unbalanced magnetrons to industrial deposition processes is discussed.

ISSN:0734-2101    

DOI:10.1116/1.576911

出版商:American Vacuum Society    

年代:1990

数据来源: AIP

摘要:

Using ion‐beam reactive sputtering of a niobium target, we have studied the effects of energetic‐nitrogen‐ion bombardment on the target reaction and on the resulting NbN film properties. Nitrogen is either added into the ion source with the noble gas to obtain a beam of nitrogen and argon ions, or injected directly into the chamber as neutral molecules so the ion beam is composed of essentially all argon. The target reaction rate is seen to be controlled by the adsorbed thermal nitrogen, and only minimally affected by the presence of ionized nitrogen. Thus, argon‐ion bombardment of the target is responsible for stimulating the reaction between the adsorbed nitrogen and the metal target producing the NbN layer. However, the film properties are affected by the presence of nitrogen ions. Films grown with N2added in the ion source have a higher resistivity and lower superconducting transition temperature than films grown with N2injected directly into the chamber. These differences increase with N2flow; the differences are attributed to damage of the growing film by energetic nitrogen reflecting from the target, as measured by an energetic‐neutral‐particle detector.

ISSN:0734-2101    

DOI:10.1116/1.576912

出版商:American Vacuum Society    

年代:1990

数据来源: AIP

摘要:

SiO2films have been prepared by hollow cathode enhanced dc reactive magnetron sputtering [J. J. Cuomo and S. M. Rossnagel, J. Vac. Sci. Technol. A4, 393 (1986)], and for comparison by rf magnetron sputtering from an SiO2target. The hollow cathode arc source is used in a triode configuration with the magnetron. This configuration allows sputtering to take place at pressures as low as 5×10−4Torr, as well as sputtering of the oxide without arcing below ∼600 V. These films were investigated as a dielectric planarization layer for Josephson (superconducting) devices. To this end, film deposition parameters (O2flow rate, Ar partial pressure, magnetron target voltage, hollow cathode current) have been related to film deposition rate, index of refraction, measured by ellipsometry, stoichiometry, measured by x‐ray photoelectron spectroscopy (XPS), and coating conformity as measured by electron microscopy. A similar set of experiments was performed for the rf sputtered films. The relationships were investigated using factorial experiment design.

ISSN:0734-2101    

DOI:10.1116/1.576914

出版商:American Vacuum Society    

年代:1990

数据来源: AIP

摘要:

Film thickness distribution control in magnetron sputtering systems is of vital importance to the researcher or process engineer, especially when performing cosputtering of superconducting and alloy films. It is time consuming to find the relative spatial position of sources, substrates, and rotational geometry by experiment to obtain optimum film uniformity. A mathematical computer model for film uniformity is developed to enable rapid prediction of optimum geometries using target erosion data. Aluminum films are deposited by rf magnetron sputtering from 100 and 75 mm diam sources at 5×10−3mbar in argon onto flat rotating workholders at various source to substrate distances and with varying source offsets from the axis of rotation of the workholder. Film thickness distribution is measured by Talystep. Target erosion profile is measured and this information is used in the computer simulation developed to predict film thickness uniformity. Practical results and theory are in good agreement, demonstrating the usefulness of the computer model. The significance of this technique is that much experimental time can be saved to find the best geometry for optimum film thickness distribution.

ISSN:0734-2101    

DOI:10.1116/1.576871

出版商:American Vacuum Society    

年代:1990

数据来源: AIP

摘要:

Thin films of Al and TiN were deposited on SiC monofilaments using a hollow cathode magnetron sputtering system. The deposition rate was 1100 Å/min in the case of Al films deposited at 45.75 W direct current power and 5 mTorr sputtering pressure and 257 Å/min for TiN films deposited at 6 mTorr sputtering pressure, 6% N2, and 48 W applied direct current power. The effects of deposition parameters such as the direct current power, sputtering pressure, and substrate bias on the film microstructure were studied. The substrate temperature varied from 67.7 to 168 °C, which corresponds to aT/Tmvalue of 0.1 to 0.25. The Al films consisted of a voided columnar structure with domed tops. The width of the grains increased with increase in temperature over aT/Tmrange of 0.1–0.22. When the pressure was increased, while keeping the power constant, the size of the columnar grains and voids decreased. The TiN films deposited at 6 mTorr exhibited zone 1 type structure with voids whereas for the films deposited at higher pressures, that is, 10 and 15 mTorr, the same effect of pressure as in the case of Al films was seen. When a bias is applied to the substrate, the voided structure is clearly suppressed. Preliminary studies show that bias sputtered films show better diffusion barrier properties against both Si and Al, after being annealed at 650 °C for 6 h, as compared to the films deposited without bias.

ISSN:0734-2101    

DOI:10.1116/1.576872

出版商:American Vacuum Society    

年代:1990

数据来源: AIP

摘要:

We have sputter‐deposited aluminum oxide coatings using a dual ion beam system with a mixture of argon plus 10% oxygen as the working gas. Ambient substrate temperatures and substrate temperatures of 360 °C were maintained. The coatings were deposited at deposition rates between 7 and 10 nm/min, with and without concurrent ion bombardment from the second ion gun. Substantial variations in the microstructure and the amount of entrained gas in the coatings were observed. The coatings contain a mixture of varying amounts of γ‐Al2O3and amorphous aluminum oxide. Relatively large, 0.5 μm islands of γ‐Al2O3crystallites surrounded by an amorphous matrix were observed in coatings deposited onto heated substrates with ion bombardment from the second ion gun during deposition. Coatings bombarded with a second ion beam during deposition contain more argon as determined by energy dispersive x‐ray analysis. The Raman spectra exhibited by the coatings suggest a variation in chemical reactivity and/or porosity which depends on the deposition conditions.

ISSN:0734-2101    

DOI:10.1116/1.576873

出版商:American Vacuum Society    

年代:1990

数据来源: AIP

摘要:

The reactive sputtering of hard coatings as TiN in large distances and/or on large substrates is difficult to perform with the conventional magnetron. A strong magnetic confinement of plasma between the magnetron target and substrates enhances the gas ionization and raises the ion currentIsextracted to substrates. A new sputtering system with a multipolar magnetic plasma confinement (MMPC) is described. It consists of a planar unbalanced magnetron (UM), with diameter 120 mm equipped with two magnetic coils, and coupled to a closed multipolar magnetic field formed by a set of permanent magnets located on the internal surfaces of the deposition chamber. Typical operation characteristics of the new sputtering system are presented. It can be operated in a wide range of pressure from 5 to 0.02 Pa. The influence of different magnetic field configurations onIsand on the floating potentialUflof substrates is also reported and compared with the characteristics of the UM without the multipolar field. Operation characteristics favorable for ion plating are observed. Ion current densitiesison substrates exceed 2 mA/cm2even at negative biasUsbelow 60 V and on substrates placed in large distances as 200 mm from the target. The floating potentialUflof substrates ranges from −5 to −50 V. Under these conditions are deposited dense golden TiN films with stresses as low as 2 to 3 GPa.

ISSN:0734-2101    

DOI:10.1116/1.576874

出版商:American Vacuum Society    

年代:1990

数据来源: AIP

摘要:

In this study, a Y target was sputtered in radio frequency (rf)‐excited, rare gas discharges (Ne, Ar) containing 0%–40% O2, operated at cathode voltage from −1.0 to −1.7 kV.Insituoptical emission spectrometry was used to monitor two neutral excited Y atom transitions (λ=0.6191, 0.6793 μm) and an excited O atom transition (λ=0.7774 μm) as a function of changing process parameter. Films were grown on fused SiO2substrates, and their crystallography, optical behavior, and electrical resistivity was determined. A ‘‘phase diagram’’ for Y–O not grown under conditions of equilibrium thermodynamics was constructed, and included hexagonal Y, cubic Y2O3, and Y and Y2O3that had no long range crystallographic order. Two direct optical transitions across the energy band gap of cubic Y2O3, at 5.07 and 5.73 eV, were identified. Combining discharge diagnostics, growth rate, and film property results, it was concluded that Y2O3was formed at the substrate concurrent with the complete oxidation of the target surface. Even after target oxidation, the discharge contained atomic Y. On the basis of fundamental optical absorption edge characteristics, cubic Y2O3that more closely resembled the bulk material was obtained when the Y‐oxide molecule/Y atom flux to the substrate was high.

ISSN:0734-2101    

DOI:10.1116/1.576876

出版商:American Vacuum Society    

年代:1990

数据来源: AIP

摘要:

ZrBxOyfilms for optical durable coating application were deposited by reactive dc magnetron sputtering of Zr–B alloy target on soda‐lime‐silica glass substrate without intentional heating. Effect of boron content on film properties was investigated. The refractive index of the film was decreased from 2.1 to 1.69 corresponding to the increase of B2O3content from 0 to 64 mol %. The films containing more than 13 mol % B2O3fraction were amorphous and showed remarkably improved mechanical durability compared with ZrO2film. More than 51 mol % B2O3content resulted in degrading of chemical durability. Measurement of mechanical properties was carried out together with characterization on crystalline structure and chemical binding state.

ISSN:0734-2101    

DOI:10.1116/1.576877

出版商:American Vacuum Society    

年代:1990

数据来源: AIP

摘要:

Thick overcoats of SiO2sputtered at high deposition rates in a radio‐frequency (rf) diode system are being considered as alternatives to Al2O3and photoresist as passivation and planarization layers in the fabrication of thin film magnetic recording heads. The mechanical properties of 7‐μm thick SiO2films sputtered onto silicon substrates were examined as functions of bias voltage and O2gas flow. A high rate of 3.69 μm/h was achieved in a production system at substrate temperatures below 40 °C. The addition of O2decreased the deposition rate to 1.65 μm/h. The decrease in deposition rate produced an improvement in thep‐etch rate, hardness and stress, but no change in the film density or morphology. The addition of a bias voltage during deposition was found to have the biggest effect on film properties. Bias sputtered films were found to be completely devoid of the columnar structure found in films deposited without bias. The addition of a small bias voltage reduced the film stress from −16×108dyn/cm2to −0.4×108dyn/cm2. However, increasing the bias voltage further caused the film stress to increase to −3.6×108dyn/cm2at −160 V bias. This effect can be correlated with the increased Ar content of the films. Thep‐etch rates of bias sputtered films dropped two orders of magnitude to 10 Å/s. The Knoop hardness increased from 423 without bias to 663 with bias and the film density increased slightly.

ISSN:0734-2101    

DOI:10.1116/1.576878

出版商:American Vacuum Society    

年代:1990

数据来源: AIP