Multipolar Magnetic Plasma Confinement Research Articles

RF Power Dependence on Structural and Electrical Properties of Cu Thin Films on a Glass Substrate Prepared Using Magnetron Sputtering with Multipolar Magnetic Plasma Confinement

RF Power Dependence on Structural and Electrical Properties of Cu Thin Films on a Glass Substrate Prepared Using Magnetron Sputtering with Multipolar Magnetic Plasma Confinement

大電力パルスマグネトロンスパッタを用いた炭素系薄膜の特性

The characteristics of diamond-like carbon (DLC) films deposited by high power impulse magnetron sputtering (HiPIMS) with multipolar magnetic plasma confinement (MMPC) were investigated. DLC films were prepared on silicon (Si) by HiPIMS and HiPIMS-MMPC over varying substrate bias voltage. Depositions were performed from a graphite target (210 mm in diameter) under argon (Ar) gas atmosphere at chamber pressure of 0.5 Pa. The DLC films were analyzed by several methods. In HiPIMS-MMPC, the peak power density was approximately 690 W/cm2 at a duty cycle of 1% (frequency: 200 Hz). According to Raman spectroscopy, the structure of DLC film deposited by HiPIMS-MMPC could be changed from amorphous carbon (a-C) to tetrahedral amorphous carbon (ta-C). The deposition rate in HiPIMS-MMPC was approximately 50% (10 nm/min) lower than that in HiPIMS. However, HiPIMS-MMPC is considered as one of the effective methods to prepare hard and dense DLC films (20 GPa and 2.00 g/cm3 at the maximum).

誘導結合プラズマ支援型多重磁極型マグネトロンスパッタ法により柔軟性素材上に作製した Ni 薄膜に及ぼすイオン照射の効果

誘導結合プラズマ支援型多重磁極型マグネトロンスパッタ法により柔軟性素材上に作製した Ni 薄膜に及ぼすイオン照射の効果

Effect of Substrate Bipolar Pulse Voltage on the Properties of Cu Films on the Paper Substrate Using Magnetron Sputtering with Multipolar Magnetic Plasma Confinement Assisted by Inductively Coupled Plasma

We have deposited Cu thin films on a water-resistant paper substrate using magnetron sputtering with multipolar magnetic plasma confinement assisted by inductively coupled plasma and investigated the effects of the substrate negative pulse voltage (Vs) and pulse frequency on the properties of the films. The X-ray diffraction results showed that the intensities of the Cu(111) and Cu(200) peaks depended strongly on both Vs and the pulse frequency. In addition, atomic force microscopy of the surface morphology revealed that increasing Vs in the range from 0 to −120 V resulted in a decrease in the root-mean-square roughness from 13.7 to 9.48 nm.

Effect of Substrate Bipolar Pulse Voltage on the Properties of Cu Films Using Magnetron Sputtering with Multipolar Magnetic Plasma Confinement Assisted by Inductively Coupled Plasma

Effects of substrate bipolar pulse voltage (Vs), pulse frequency and duty ratio on the properties of Cu thin films using magnetron sputtering with multipolar magnetic plasma confinement assisted by inductively coupled plasma (MMPC-ICP) were demonstrated. Results from X-ray diffraction (XRD) show that the intensities of the Cu(111) and Cu(200) peaks depend strongly on the Vs. The intensity of the XRD peak for Cu(111) increased when the Vs was increased from 0 V to −120 V. It is shown that the Cu film deposited at Vs=−120 V has a maximum grain size of about 42.6 nm; this value is about 1.5 times higher than that at Vs=0 V.

多重磁極型高周波マグネトロンスパッタ法によるＣｏ薄膜の基板温度依存性

The dependence on substrate temperature of the structural properties of Co thin films deposited on silicon substrates by RF magnetron sputtering with multipolar magnetic plasma confinement (MMPC) was investigated. The structure of the Co films was characterized by X-ray diffraction (XRD), and their surface morphology by atomic force microscopy (AFM). It was found that the surface morphology depended strongly on the substrate temperature. The surface of Co thin films deposited at 400°C exhibited round connected textures with a maximum Rq (root mean square roughness) of 5.48 nm, while the films deposited at room temperature exhibited salient connected textures with an Rq of less than 1.18 nm. Furthermore, the XRD spectrum intensity observed for the Co films deposited at 400°C was higher than that of the films deposited at room temperature.

多重磁極マグネトロンスパッタ法により作製したＣｏ及びＣｕ薄膜の電磁波シールド効果

Electromagnetic wave shield characteristics were studied for Co and Cu thin films prepared by magnetron sputtering with multipolar magnetic plasma confinement (MMPC) . The characteristics were measured utilizing the Kansai Electronic Industry Development Center (KEC) Method. Results show that the electric field and magnetic field shield effects depend significantly on the thickness of the Co and Cu thin films. The shielding effectiveness of 1 μm-thick deposited Co films for electric and magnetic fields was 69 dB and 51 dB, respectively, measured at 800 MHz. For Cu films, the effectiveness was 77 dB and 61 dB, respectively. It was demonstrated that the electromagnetic wave shield effeet of Co and Cu thin films, which is dependent upon the film thickness, is the result of attenuation loss and the skin effect.

誘導結合プラズマ支援型多重磁極マグネトロンスパッタ法により作製したＣｕ薄膜に及ぼす陽極電圧と基板バイアス電圧の効果

The effect of substrate dc bias voltage (VS) and anode dc voltage (VA) on the properties of Cu thin films using magnetron sputtering with multipolar magnetic plasma confinement assisted by inductively coupled plasma (MMPC-ICP) was characterized by X-ray diffraction (XRD) and Atomic Force Microscope (AFM). The anode electrode was placed at a distance of 10 mm from the substrate in the MMPC-ICP system in order to increase the plasma density near the substrate. It is demonstrated that an increase in VA results in a decrease in the VS voltage at which the substrate current begins to saturate. The Cu thin films were prepared by changing the substrate dc bias voltage from -100 V to 0 V at the different anode voltages ranging from 0 V to 40 V. It is shown that the Cu film deposited at VA=40 V and VS=-20 V has a maximum grain size of about 430 nm; this value is about 5 times higher than that at VA=0 V and VS=-20 V.

In situ observation of ordering process in FePt films during annealing in a transmission electron microscope

We have investigated the process of the phase transformation from fcc to fct in FePt thin films by in situ observation during annealing in a transmission electron microscope. The coercivity for the in-plane field increases drastically up to about 6.3kOe by annealing at 300°C in the film prepared at 0.5mTorr by multipolar magnetic plasma confinement sputtering. The as-deposited film has a flat surface and very large grains of 8–16nm, which causes the easy ordering at low temperatures. The ordering progresses accompanied with the crystal growth, which occurs laterally by the coalescence with the disordered grains. On the other hand, in the film prepared at 5mTorr by the conventional sputtering, the surface is rough and grains are smaller than 6nm. This small grain in the as-deposited state suppresses the crystal growth and also the ordering even at higher annealing temperatures.

誘導結合プラズマ支援型多重磁極マグネトロンスパッタ法により作製したニッケル薄膜の基板バイアス電圧依存性

The dependence of substrate dc bias voltage on structural properties of Ni thin films using magnetron sputtering with multipolar magnetic plasma confinement (MMPC) assisted by inductively coupled plasma (ICP) was investigated. When magnetron sputtering with MMPC assisted by ICP was applied, the current flowing into the substrate due to Ar+ ions and sputtered Ni+ ions was increased. Ni thin films were deposited due to the ions energy controlled by each substrate dc bias voltage from 0 V to -80 V. The Ni thin films were analyzed by X-ray diffraction (XRD) and a transmission electron microscope (TEM). It is shown that applying the substrate dc bias voltage results in a significant change of the relative intensity of the orientation of (111) plane and an increase in the grain size.

誘導結合プラズマ支援型多重磁極マグネトロンスパッタ法によるニッケル成膜時の基板電流特性

The discharge characteristics in magnetron sputtering of Ni with multipolar magnetic plasma confinement (MMPC) assisted by inductively coupled plasma (ICP) were investigated. When sputtering with MMPC assisted by ICP, the current flowing into the substrate due to Ar+ ions and sputtered Ni+ ions is increased up to 46 mA, about 2.7 times that of a conventional magnetron sputtering system. The substrate current significantly increases in comparison with a conventional magnetron sputtering system as the target dc bias voltage increases. It is shown that a nickel film with the orientation of (111) plane is formed by using ICP.

High coercive FePt alloys prepared by a new sputtering method

Fe–Pt films have been prepared on glass substrates kept at room temperature by a new sputtering method of multipolar magnetic plasma confinement. In the films having near stoichiometric composition of 53at%Pt, the transition temperature from the disordered Fe–Pt FCC to the L10-ordered phase can be decreased drastically to 300°C, where the clear peaks indicating L10 structure and then the high coercivity of 7kOe appear. This paper discusses the effects of the sputtering condition on the ordering temperature and the crystalline structure.

多重磁極マグネトロンスパッタ法により作製したＮｉ薄膜の電磁波シールド効果

Nickel thin films for an electromagnetic wave shield were produced by magnetron sputtering with multipolar magnetic plasma confinement (MMPC). The characteristics of the electromagnetic wave shield have been measured by the Kansai Electronic Industry Development Center (KEC) method. The effectiveness of the electromagnetic wave shields of electric field and magnetic field depends significantly on the thickness of Ni thin films deposited on the glass substrate. The shielding effectiveness of the electric field, measured at 800 MHz for 5 μm-thick deposited films, was 92 dB. The value was similar to a 2 mm-thick aluminum plate. For the magnetic field, its effectiveness was 73 dB. It is shown that the dependence of film thickness on the electromagnetic wave shield is due to attenuation loss.

多重磁極マグネトロンスパッタリング法で作製したＦｅ‐Ｎ薄膜の磁化特性と膜構造

Thin films of Fe and Fe-N have been prepared using an rf magnetron sputtering system equiped with multipolar magnetic plasma confinement (MMPC), which is efficient for preparation of ferromagnetic thin films at low pressures. For sputtering with 150 W rf-power, the deposition rate of Fe film is 12-14 nm/min, which is three times larger than that of conventional planar magnetron sputtering system. Iron nitride films have been sputter-deposited in an Ar-N2 gas mixture at several pressures, Psp, of 5-0.6 mTorr and the gas flow ratio, fN2 = N2/(Ar + N2), of 0-0.6. The crystalline and morphological structures, the nitrogen content in the film, and the resistivity depend strongly on Psp and fN2. These dependences are explained by the energy of sputtered particles reached at the film surface. In particular, the films prepared at 0.6 mTorr, which is realized by MMPC method, exhibit the crystalline structures of Fe, Fe4N and Fe3N phases depending on fN2, and show the very high purity.

多重磁極形高周波マグネトロンスパッタ法によるＦｅ薄膜のスパッタガス圧力依存性

Iron thin films were prepared by using an r. f. magnetron sputtering technique with multipolar magnetic plasma confinement, which is efficient for preparation of ferromagnetic thin films at a low gas pressure (1.1 Pa8 × 10-2 Pa). It is shown that lowering the sputtering gas pressure down to 8 × 10-2 Pa results in a significant decrease in the resistivity close to the bulk value of Fe. The intensity ratio of [FeOx] / ([Fe] + [FeOx]) obtained from X-ray photoelectron spectroscopy spectra decreased with the lowering of the sputtering gas pressure. Also, the oxygen content in the film deposited at a low gas pressure of 8 × 10-2 Pa is reduced to below the detection limit of XPS. It is demonstrated that the intensity of Fe (110) peak using XRD increases as the sputtering gas pressure decreases.

High rate sputtering for Ni films by an rf-dc coupled magnetron sputtering system with multipolar magnetic plasma confinement

Ni films were prepared by an rf-dc coupled magnetron sputtering with multipolar magnetic plasma confinement (MMPC) at the low pressure of 6.7×10−2 Pa and at the long distance of 120 mm, when permanent magnets were placed around a nickel target (200 mm φ, 5 mm thick) outside the chamber. When rf power and dc bias voltages were applied simultaneously to the target, the deposition rate of the Ni films significantly increased with the target dc bias voltage (VT). The highest value of the deposition rate was about 250 nm/min at VT=−820 V. The high rate sputtering for Ni films was possible at the low Ar gas pressure of 6.7×10−2 Pa. The resistivity for all the films deposited at different dc bias voltages was 7.1–8.2 μΩ cm whose value was close to the bulk value. It is shown that the sputtering system with MMPC has some advantages in comparison with conventional magnetron sputtering, such as high deposition rate, plasma discharge stability, and the preparation of high quality magnetic thin films.

Microstructure and electrical properties of CoN X thin films deposited by unbalanced magnetron sputtering

The structure and electrical properties of cobalt nitride (CoN X ) thin films, prepared by newly developed r.f. reactive sputtering with magnetically enhanced ionization by means of multipolar magnetic plasma confinement (MMPC), were studied. In an unbalanced magnetron sputtering system with MMPC, ferromagnetic materials can be sputtered at a low gas pressure (8.0×10 −2 Pa). It was found that lowering the total gas pressure (Ar+N 2) down to 8.0×10 −2 Pa resulted in a decrease in the resistivity of the films, whose value is about 10 μΩ cm. The average size of the grain decreased with a decrease in the total gas pressure. Nanocomposite films of cobalt nitride with an average grain size of about 5 nm were formed by lowering the total gas pressure.

Sputtering systems with magnetically enhanced ionization for ion plating of TiN films

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 current Is extracted 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 on Is and on the floating potential Ufl of 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 densities is on substrates exceed 2 mA/cm2 even at negative bias Us below 60 V and on substrates placed in large distances as 200 mm from the target. The floating potential Ufl of 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.