A comparative study of direct current magnetron sputtering and high power impulse magnetron sputtering processes for CNx thin film growth with different inert gases

Abstract

A comparative study of direct current magnetron sputtering and high power impulse magnetron sputtering processes for CNX thin film growth with different inert gases, 2016, Diamond and related materials, (64), [13][14][15][16][17][18][19][20][21][22][23][24][25][26] ABSTRACTReactive direct current magnetron sputtering (DCMS) and high power impulse magnetron sputtering (HiPIMS) discharges of carbon in different inert gas mixtures (N2/Ne, N2/Ar, and N2/Kr)were investigated for the growth of carbon-nitride (CNx) thin films. Ion mass spectrometry showed that energies of abundant plasma cations are governed by the inert gas and the N2-to-inert gas flow ratios. The population of ion species depends on the sputter mode; HiPIMS yields approximately ten times higher flux ratios of ions originating from the target to process gas ions than DCMS.Exceptional are discharges in Ne with N2-to-Ne flow ratios < 20%. Here, cation energies and the amount of target ions are highest without influence on the sputter mode. CNx thin films were deposited in 14% N2/inert gas mixtures at substrate temperatures of 110 ºC and 430 ºC. The film properties show a correlation to the substrate temperature, the applied inert gas and sputter mode.The mechanical performance of the films is mainly governed by their morphology and composition, but not by their microstructure. Amorphous and fullerene-like CN0.14 films exhibiting a hardness of ~15 GPa and an elastic recovery of ~90 % were deposited at 110 ºC in reactive Kr atmosphere by DCMS and HiPIMS.

Low-temperature growth of boron carbide coatings by direct current magnetron sputtering and high-power impulse magnetron sputtering

“…The average particle energy can be estimated to be less than 10 eV on the basis of results in Ref. [29] (cf. Fig.…”

“…This implies not only benefits with regard to the film morphology and density, but also for the residual stress [26,27] and the step coverage [21]. Although ion bombardment of the growing film has frequently been reported to yield high film stresses [28], the comparison of films deposited by DCMS and HiPIMS showed significantly reduced stresses without sacrificing film hardness or density in case HiPIMS was used [29]. Here, mainly the sputter gas and target material properties, i.e., mass and ionization potentials, together with appropriate bias voltage setting were found decisive.…”

“…3a, f black lines in Ref. [29]), given that the peak target currents in the HiPIMS B 4 C processes did not exceed 72 A and the discharge characteristics of B 4 C were found to be similar to graphite. Moreover, in order to provide well-adhering coatings, the processes were conducted at floating potential, which maintains low particle energies at the growing film surface.…”

SiNx coatings deposited by reactive high power impulse magnetron sputtering: Process parameters influencing the residual coating stress

“…22,23 The reduced stress in films deposited by HiPIMS is commonly attributed to the method's inherent increased flux of ionized target material together with a decreased flux of ionized working gas and implies a moderate total flux of ions. [24][25][26][27][28] This is particularly the case for the metal-ion rich phase of the HiPIMS pulse.…”

“…[24][25][26][27][28] This is particularly the case for the metal-ion rich phase of the HiPIMS pulse. 22,23 Here, the generation of the intrinsic coating stress induced by energetic particle bombardment can be substantially decreased if additionally the applied substrate bias voltage is synchronized to this metal-ion rich phase of the pulse to avoid bombardment by inert gas ions and doubly charged metal ions. 22 However, this approach may only be of advantage for process setups using a specific target material -inert gas combinations providing a practical temporal discrimination of the plasma species and a setup that uses one cathode that is operated in HiPIMS mode as well as flat substrates, where the substrate rotation is not required.…”