The effect of substrate bias on the piezoelectric properties of pulse DC magnetron sputtered AlN thin films

Substrate bias was applied for AlN deposition on rolled Ni sheet during pulse DC reactive sputtering to overcome the difficulty caused by thermal expansion mismatch between Ni substrate and AlN upon substrate heating. It was shown by Piezoresponse Force Microscopy (PFM) that the quality of the deposited AlN layer depends strongly on the negative substrate bias, i.e., the energy transferred via the bombardment of the accelerated positive ions on the sample. As the negative substrate bias becomes larger, the so formed layer shows higher piezoresponse, and better homogeneity. A Z-cut LiNbO3 single crystal was used as a reference to correct the PFM signals. The highest average d33 piezoelectric coefficient value, achieved at − 100 V substrate bias, is 3.4 pm/V indicating the feasibility of AlN deposition on rolled Ni substrate for vibration energy harvesting applications.

SURFACE MORPHOLOGY OF SPUTTERED TITANIUM-ALUMINUM-NITRIDE COATINGS

A study on the surface morphology of sputtered TiAlN coatings is presented. The coatings were deposited by DC magnetron sputtering on tungsten carbide insert tools. The surface morphology was characterized by using Atomic Force Microscopy (AFM), and the surface roughness was indicated by RMS roughness value. It was observed that the TiAlN coating surface morphology was rough as the negative substrate bias and nitrogen flow rate are increased. The evolution of the sputtered TiAlN coatings surface morphology was due to the competition between particle diffusion and re-scattering effect during the sputtering process. At high negative substrate bias and nitrogen flow rate, the re-scattering effect was prominent, leading to the high roughness of the sputtered TiAlN coating surface.

DEPOSITION OF TiN-BASED COATINGS USING VACUUM ARC PLASMA IN INCREASED NEGATIVE SUBSTRATE BIAS VOLTAGE

The paper presents the results of the study on the influence of a high substrate bias voltage from 300 up to 1300 V on the titanium nitride coating deposition under nitrogen pressure of 2 Pa. The deposition rate, phase and chemical composition, adhesion and mechanical properties of coatings, macroparticle number and size distribution were investigated.

Electrical properties of FCVA deposited nano-crystalline graphitic carbon thin films with in situ treatment techniques

In this report, detailed studies of the nano-crystalline graphitic (NCG) carbon thin films deposited by filtered cathodic vacuum arc (FCVA) following its first discovery and first electrical characterization have been performed. The microstructure of carbon thin film can be modified by applying in situ treatment techniques (such as altering the thermal and carbon ion deposition energy). It was found that highly electrical conductive carbon thin films with graphitic planes can also be deposited at a low deposition temperature instead of the previously reported high deposition temperature with a 20% improvement in electrical characteristic. The detailed electrical characterization comparison between amorphous carbon and NCG has been conducted. To conclude, NCG carbon can be fabricated at deposition temperature above 400 °C and exhibits increasing through film Ohmic electrical conductivity with increasing deposition temperature. At low temperatures, NCG carbon can be produced by increasing the negative substrate bias above 300 V (impinging carbon ion energy). Higher negative substrate bias leads to thinner amorphous interface layer hence better electrical conductivity.

The Influence of the Bias on Mechanical Properties of a-C:H CVD Thin Films

In this study a-C:H (hydrogenated amorphous carbon) thin films were deposited on the 7075 Al alloy without an interlayer using a DC CVD (direct current chemical vapor deposition) method with varied negative substrate bias in order to improve the hardness and Young´s modulus. The highest values of films hardness and Young´s modulus were 25.6±3.5 GPa and 140.3±4.6 GPa, respectively. The measured results show a promising potential of the a-C:H coated 7075 Al alloy for low load (up to 10 N) applications.

Effects of Substrate Bias on Tribological Properties of Diamondlike Carbon Thin Films Deposited Via Microwave-Excited Plasma-Enhanced Chemical Vapor Deposition

In this study, the structure and tribological performance of the diamondlike carbon (DLC) films were related to deposition parameters. The feasibility of the microwave-excited plasma-enhanced chemical vapor deposition (μW-PECVD) as a process to produce good quality DLC films was the focus. The DLC films were deposited on the steel substrates with a tungsten carbide interlayer via μW-PECVD. The negative substrate bias used during the film deposition was varied. The Raman results revealed that the increased negative substrate bias increased the sp3 bonding in the DLC films as a result of the increased kinetic energy of film-forming ions during the film deposition. The tribological results clearly indicated that the friction and wear of the DLC-coated steel samples against a 100Cr6 steel ball significantly decreased with increased negative substrate bias due to the significantly improved wear resistance of the DLC films.

Controlling nanowire nucleation and growth with a negative substrate bias

Applying a voltage bias to silicon nanowires during growth can influence wire density, diameter and length.