The Effect of Match between High Power Impulse and Bias Voltage: TiN Coating Deposited by High Power Impulse Magnetron Sputtering

Chi-Lung Chang,Ching-Yen Lin,Jian-Fu Tang,Fu-Chi Yang

doi:10.3390/coatings11070822

Chi-Lung Chang, Ching-Yen Lin + Show 2 more

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https://doi.org/10.3390/coatings11070822

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Abstract

Practical experience in the use of high power impulse magnetron sputtering (HiPIMS) technology has revealed that output bias current depends on the total energy output of the cathodes, which means that bias voltage settings do not necessarily match the actual output. In this study, we investigated the effects of bias current and voltage on the characteristics of titanium nitride thin films produced using high impulse magnetron sputtering. The bias current and voltage values were adjusted by varying the supplied cathode power and substrate bias under DC and pulsed-DC output models. Our results revealed that pulse delay (PD) and feed forward (FF) settings can be used to control bias current and voltage. Increasing the bias current from 0.56 to 0.84 was shown to alter the preferred orientation from (111) to (220), increase the deposition rate, and lead to a corresponding increase in film thickness. The surface morphology of all titanium nitride samples exhibited tapered planes attributable to the low bias current and voltage (−30 V). The maximum hardness values were as follows: DC mode (23 GPa) and pulsed-DC mode (19 GPa). The lower hardness values of pulsed-DC samples can be attributed to residual stress, preferred orientation, and surface morphology. The surface of the samples was shown to be hydrophobic, with contact angles of >100°.

Highlights

Titanium nitride (TiN) is a protective coating widely used in cutting tools and mechanical components in the aerospace industry, due to its high hardness and excellent wear and corrosion resistance [1,2,3]
Software was used to synchronize the operations of the two highpower impulse magnetron sputtering (HiPIMS) power supplies, i.e., establish set intervals between the operations of Coatings 2021, 11, x FOR PEER REVIEW
The surface morphology created under P-DC output presented a larger proportion of pyramidal grains than was observed in samples created under DC mode

Summary

Introduction

Titanium nitride (TiN) is a protective coating widely used in cutting tools and mechanical components in the aerospace industry, due to its high hardness and excellent wear and corrosion resistance [1,2,3]. HiPIMS power supplies with large capacitors tend to produce pulses of high currents, which is amenable to the deposition of high-density films with low surface roughness [17]. That the instantaneous delivery of a high current and voltage at the instant arcing occurs can trigger the power supply to switch off, which increases the degree of uncertainty in the deposition process. During the film deposition process, high currents and voltage are generated at the instant arcing occurs, causing the DC-bias output of the substrate to be interrupted via the above-mentioned protection mechanism. Under these circumstances, the deposition rate is low, and the adhesion of the resulting film is poor. Samples were created using eight combinations of PD and FF under DC or P-DC bias output modes in order to elucidate the effects of bias current and voltage on the microstructural and mechanical characteristics of TiN thin films

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Results and Discussion

Conclusions