RF-DC Coupled Magnetron Sputtering Research Articles

高周波－直流結合形マグネトロンスパッタリング法によるＧｅ－Ｎ系薄膜の作製

高周波－直流結合形マグネトロンスパッタリング法によるＧｅ－Ｎ系薄膜の作製

高周波‐直流結合形マグネトロンスパッタ法におけるＡｒ｀＋´及びＣｕ｀＋´イオンのエネルギー分布

Energy distribution of 40Ar+ ions and 63Cu+ ions incident to the substrate surface in rf-dc coupled magnetron sputtering with which an rf source and a dc power were simultaneously applied to a copper target in order to control the incident ion energy on the target were measured by an energy-resolved mass spectrometer. The target power (rf+ dc) was varied from 2.0 to 5.0 kW at an Ar gas pressure of 1.0 Pa. The mean energy of 40Ar+ ions and 63Cu+ ions shifted from about 11.0 to 3.0 eV with the increase of the ratio of dc power to rf power. The number of 63Cu+ ions significantly increased with the increase of the target power, whose value was about 500 times the number of 40Ar+ ions at the target power of 5.0 kW.

New sputter-deposition processes for the formation of thin films with desired structure for magnetic recording

Two new sputter-deposition techniques, low voltage sputtering (LVS) and kinetic energy controlled particle deposition (KECD), are proposed to obtain a thin film with the desired microstructure. The LVS, RF–DC coupled magnetron sputtering with RF frequency above 30 MHz, is useful for sputtering at a sputtering voltage below 100 V and has a reasonable deposition rate. Indium tin oxide (ITO), Ti and CoCrTa films were deposited by using the LVS. Compared with conventional sputtering, LVS is effective in reducing high-energy particle bombardment of film surfaces during sputtering, which results in the formation of films with much smoother surfaces, although crystallization in the film is suppressed. On the other hand, KECD can control the kinetic energy and incidence angles of the depositing particles on the substrate. With KECD, it was confirmed that crystal growth is suppressed as the kinetic energy decreases in ITO film and the crystal orientation of Ti film depends remarkably on the kinetic energy of the deposition particles. Films with extremely smooth surface are obtained by KECD.

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.

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

The effect of the dc bias on the compositional ratio, resistivity, and deposition rate for tungsten nitride (WN X ) films prepared by rf-dc coupled magnetron sputtering have been investigated in detail. The value of the film compositional ratio (N/W) is significantly decreased from 0.8 to 0.2 with increasing the target dc bias voltage. The increase of the target dc bias voltage from −100 to −500 V results in a dramatical decrease in the resistivity of WN X films. It is shown that the N/W ratio and the resistivity of WN X thin films deposited at the target dc bias voltage of −200 V are about 0.5 and 370 μΩ cm, respectively.

最近のスパッタリングとイオンプレーティング技術 高周波‐直流結合形マグネトロンスパッタリングによる薄膜物性制御

最近のスパッタリングとイオンプレーティング技術 高周波‐直流結合形マグネトロンスパッタリングによる薄膜物性制御

高周波‐直流結合形マグネトロンスパッタ法によるＷＮｘ薄膜の作製とＣｕ／ＷＮｘ／Ｓｉ構造の拡散バリア効果

Tungsten nitride (WNX) thin films have been prepared using an RF-DC coupled magnetron sputtering system, in which the incident ion energy on the target can be controlled by the target DC bias voltage. The films were applied to Cu/WNX/Si samples and the obtained Cu (500 nm) /W2N (25 nm) /Si samples were stable without Cu-Si reaction after annealing at 700°C for 30 min. It was shown that the film composition (N/W) can be controlled by the target DC bias voltage without changing the gas flow ratio (N2/ (Ar+ N2)), and the N/W ratio was decreased from 0.8 to 0.2 only by increasing the target DC bias voltage from -100 V to -500 V, respectively, at the N2/ (Ar + N2) ratio of 0.2.

Low energy rf sputtering system for the deposition of ITO thin films

An rf–dc coupled magnetron sputtering system was used to deposit ITO thin films at a target potential above −100 V. The energy of the ions incident to the target surface during sputtering, i.e., the target cathode potential, was controlled by means of a dc high voltage power supply, and the number of the ions striking the target was controlled by adjusting the input power to the sputtering system from the rf power supply. The frequency of the rf power supply was changed in the range from 10–100 MHz to maintain the target potential above −100 V during sputtering. ITO films were deposited at various target potentials. The resistivity of the film decreased steeply as the target potential increases from −300 to −100 V, and the minimum resistivity was as low as 5×10 −4 Ω cm. This decrease in resistivity was caused by an increase in carrier mobility and carrier density in the films. The smoothness of the film surface was also significantly improved by increasing the target potential.

Preparation of argon-free refractory thin films using RF-DC coupled magnetron sputtering

The process of argon-free refractory metal (Mo and Ta) thin films in a RF-DC coupled magnetron sputtering system was investigated experimentally and by use of Monte Carlo simulation. While for accommodation of Ar atoms in growing Ta films the threshold energy of 200 eV was obtained, for the case of Mo films it could be possible to estimate only the lower limit for this threshold energy as 120 eV.

Preparation of Mg xNi thin films by RF-DC coupled magnetron sputtering

Mg x Ni thin films have been prepared by an RF-DC coupled magnetron sputtering technique. RF power and DC bias were simultaneously applied to the target in order to control the incident ion energy on the target. When a low RF power and DC bias are applied simultaneously to the target, the glow discharge takes place at a low DC bias and the target DC current increases smoothly as compared with the DC mode magnetron case. The values of the film compositional ratio Ni/Mg were obtained in the range of 1.19–0.56 at target DC bias voltages of — 50- − 200 V without changing the target area ratio of Ni to Mg. The crystalline structure of Mg x Ni films is influenced by the target DC bias.

Effect of DC bias on the deposition rate using RF-DC coupled magnetron sputtering for Mg thin films

The dependence of the deposition rate of Mg thin films on a DC bias using RF-DC coupled magnetron sputtering was investigated. When an extremely low RF power (5 W) and DC bias were applied simultaneously to the target, the glow discharge took place at a low DC bias of −30 V whose value was obtained about one-fifth of the conventional DC magnetron sputtering case. Mg films have been prepared at the RF power value of 5 W and the DC bias voltage values of −50- −200 V. The obtained values of the deposition rate varied from 9–62 nm/min. It is shown that the film growth coefficient (deposition rate/ion current density) of Mg films is significantly influenced by the target DC bias.

高周波‐直流結合形マグネトロンスパッタ法によるＴｉＮｘ／Ｓｉ系の電気的特性

The Schottky barrier diodes of sputtered TiNx on n-type silicon have been prepared by an RF-DC coupled magnetron sputtering system which employs a low RF power and DC bias. The electrical properties of TiNx/Si system prepared by this method have been investigated. It was found that the TiNx/Si system prepared at the target DC bias voltage of-100 V have the Schottky barrier with low sputtering damage where the Schottky barrier height is 0.56 eV. It was suggested that the RF-DC coupled magnetron sputtering is useful for preparation of the Schottky barrier diode.

Preparation of Ta/Mo structure by using RF-Dc coupled magnetron sputtering

RF power and DC bias have been simultaneously applied to the target in a conventional magnetron sputtering system in order to control the growth kinetics of Ta films. Lowering the target DC bias V1 down to −100 V results in a significant decrease in the Ar content in the Ta film, which is reduced to below the detection limit of electron prove microanalysis (EPMA, less than 0.05 wt.%) for VT = −100V. It is shown that the resistivity and the crystalline structure of the Ta thin overlayer on every thin film of Mo depend on the thickness of Mo films. The resistivity for Ta films with α-Ta phase at the very thin Mo films (about 1 nm) was obtained at ∼20 μ Ω cm, whose value was one seventh of that for the Ta films without the underlayer Mo thin films.

Ａｒ‐Ｎ２混合ガスを用いた高周波 直流結合形マグネトロンスパッタ法による窒化マグネシウム薄膜の作製

In an RF-DC coupled magnetron sputtering system, the magnetron discharge was generated by a 13.56 MHz RF source, and a DC power supply was simultaneously applied to the target. When a low RF power and DC bias are applied simultaneously to the Mg target, the glow discharge during Ar-N2 plasma takes place at a low DC bias and the target DC current increases smoothly compared with the DC mode magnetron case. MgNx films have been prepared at the gas flow ratio (N2/ (Ar+N2)) of 0.2 by an RF-DC coupled magnetron sputtering. It was shown that the MgNx films are obtained at the target bias VT=-100 V, where the compositional ratio (N/Mg) is 0.44.

Monte Carlo simulation of argon atoms transport during deposition of W thin films by RF-dc coupled magnetron sputtering

RF power and DC bias have been simultaneously applied to the target in a conventional magnetron sputtering system in order to control the growth kinetics of W thin films using argon gas for sputtering. A Monte Carlo simulation based on physical models of ion-plasma sputtering was carried out to study the dependence of Ar concentration in the tungsten film on the parameters of the discharge, and on the flow of argon atoms onto the substrates. An energy of 180 eV was proposed as a threshold for accommodating Ar atoms in growing W films.

Transparent, conductive CuI films prepared by rf-dc coupled magnetron sputtering

Optically transparent, conducting Cul films have been prepared by a magnetron sputtering technique which employs rf and dc target biases. It is shown that the stoichiometric Cul films are obtained at the target bias V T= −200 V, while the lowest resistivity of 5.4 × 10 −2 Ω cm and the best optical transmittance of about 70% over the wavelength range 500 to 1000 nm are obtained at V T= −50 V where the I/Cu

ＲＦ‐ＤＣ結合形マグネトロンスパッタ法によるＷ薄膜の作製

ＲＦ‐ＤＣ結合形マグネトロンスパッタ法によるＷ薄膜の作製