Magnetron Sputter Type Negative Ion Research Articles

The luminescence and optoelectrical properties of ITO films prepared by a sputter type negative metal ion deposition

Transparent conducting indium tin oxide (ITO) thin films were prepared on glass substrates by a magnetron sputter type negative ion source which requires cesium (Cs) vapor injection for surface negative ionization on the ITO target surface. Although the film was prepared at 70°C, it attained high optical transmittance, 88% and low resistivity, 2.03×10−4Ωcm, at an optimized Cs partial pressure of PCs=1.7×10−3Pa. The as-deposited ITO films have a poly-crystalline structure with (211), (222), (400), (411) and (440) reflections.Also, ITO films prepared at PCs=1.7×10−3Pa were post-deposition vacuum annealed at 300°C for 30min. The films had a resistivity of 1.8×10−4Ωcm and a transparency of 89.2%. The post-deposition vacuum annealed ITO film was used as an anode for a transparent organic light emitting diode (TOLED). A maximum luminance of 19,000cd/m2 was obtained.

Characteristics of Cu films prepared using a magnetron sputter type negative ion source (MSNIS)

Cu films have been deposited at room temperature using a magnetron sputter type negative ion source (MSNIS) at various conditions. By the principle of operation, the negative ion production probability is the function of the Cs flow rate in MSNIS. A set of films were deposited at different Cs flow rates and compared with normal-magnetron-sputtered films. The long-throw method was combined to MSNIS to increase the directionality and the negative ion arrival ratio. The film properties, such as resistivity, surface roughness, film structure, and step coverage on high aspect-ratio trench samples were obtained and analyzed using SEM, SIMS and AFM methods. The results showed that the resistivity of the film improved toward the theoretical values from 2.3 to 1.8 μΩ cm for the 100 nm thickness films. AFM scan of the film showed surface roughness was improved using MSNIS by ion bombarding effect. Depth profiling SIMS result showed Cs level resided in the film was less than 1 × 10 19 at./cm 3. As an application, Cu seed layer deposition on trench structure was investigated. Cross-sectional SEM was employed to see the step coverage of the film. The biasing effect was investigated. The different biasing conditions resulted as the clearly different coverage mode.

Characteristics of Cu films prepared using a magnetron sputter type negative ion source (MSNIS)

Cu films have been deposited at room temperature using a magnetron sputter type negative ion source (MSNIS) at various conditions. By the principle of operation, the negative ion production probability is the function of the Cs flow rate in MSNIS. A set of films were deposited at different Cs flow rates and compared with normal-magnetron-sputtered films. The long-throw method was combined to MSNIS to increase the directionality and the negative ion arrival ratio. The film properties such as resistivity, surface roughness, film structure and step coverage on high-aspect ratio trench samples were obtained and analyzed using SEM, SIMS and AFM methods. The results showed that the resistivity of the film improved toward the theoretical values from 2.3μΩcm to 1.8μΩcm for the 100nm thickness films. AFM scan of the film showed surface roughness was improved using MSNIS by ion bombarding effect. Depth profiling SIMS result showed Cs level resided in the film was less than 1×1019atom/cm3. As an application, Cu seed layer deposition on trench structure was investigated. Cross-sectional SEM was employed to see the step coverage of the film. The biasing effect was investigated. The different biasing conditions resulted as the clearly different coverage mode.

High-density DLC films prepared using a magnetron sputter type negative ion source

Diamond-like carbon (DLC) films have been deposited at room temperature using a magnetron sputter type negative ion source (MSNIS). The film characteristics such as density, surface roughness, film structure and thicknesses are obtained and analyzed using X-ray reflectivity (XRR), XPS and AFM methods. XRR results showed that the density of the film varies from 1.9 to 3.0 g/cm 3 with respect to the different deposition parameters. At average negative carbon ion energy 700 eV and Cs injector temperature 150 °C, the densest film (3.0 g/cm 3) was observed at 1 nm/s deposition rate. The surface roughness of the film was less than 1.0 nm in most cases for the 10-nm thickness film. XPS peak showed no Cs content on the film. The films prepared at different negative ion production yields and negative ion energies were compared. The result suggests that the density is the strong function of negative ion energy and the negative ion production yield. Higher cathode voltage induced denser film, while Cs flow rate had optimum temperature condition around 150 °C.

The stability of SiO 2 films prepared using a magnetron sputter type negative ion source (MSNIS)

Aging effect of SiO 2 films was investigated. SiO 2 films were prepared using a magnetron sputter type negative ion source (MSNIS) utilizing the direct ion beam deposition (DIBD) method. Thin SiO 2 films are known as suffering from aging effect after the deposition. To minimize the variation of the refractive index or thickness of the film after the long period of time, a dense film is desirable. The optical properties such as refractive index ( n), extinction coefficient ( k) and thickness were analyzed using an UV spectrometer-combined thin-film measurement system. The surface morphology and roughness were measured using an atomic force microscope (AFM). The thickness and refractive index variance after 1-month period was less than 3% for the 100 nm thickness films. The average roughness of the film on silicon substrate was less than 1 nm in most cases. The resultant films show that the film properties were strongly dependent on the ion beam energy and oxygen partial pressure of deposition. In high power density (3.2 W/cm 2), the aging effect was more noticeable. The wet-etch test of SiO 2 films with respect to Cs flow rate showed that Cs flow rate is an important parameter in operation of a MSNIS.

Characterization of the Sn Doped In2O3 Film Prepared by DC Magnetron Sputter Type Negative Metal Ion Beam Deposition

Transparent conducting indium tin oxide (ITO) films were prepared on a glass substrate by DC magnetron sputter type negative ion source from a target of a mixture of In2O3 (90%) and SnO2 (10%). In order to investigate the influence of cesium (Cs) partial pressure (PCs) on the optoelectronic property of ITO films, the PCs was varied from 1×10-3 to 2.2×10-3 Pa. The O2/Ar flow rate, working pressure, power density, and substrate temperature were kept constant at 3.6%, 9×10-2 Pa, 2.5 Wcm-2 and 70°C, respectively. By optimizing the PCs at 1.7×10-3 Pa, transparent (transmission ∼81% at 550 nm) and conducting (resistivity ∼4.3×10-4 Ωcm) ITO films were prepared. Atomic force microscopy (AFM) images showed that the surface morphology also varied significantly with PCs and that the lowest surface rms roughness was 0.6 nm measured at PCs=1.7×10-3 Pa. XPS measurement showed that the Cs concentration in the ITO films was less than 0.2 at%.