Strategy for tuning the average charge state of metal ions incident at the growing film during HIPIMS deposition

Abstract

Energy-and time-dependent mass spectrometry is used to determine the relative number density of singly-and multiply-charged metal-ion fluxes incident at the substrate during highpower pulsed magnetron sputtering (HIPIMS) as a function of the average noble-gas ionization potential. Ti is selected as the sputtering target since the microstructure, phase composition, properties, and stress-state of Ti-based ceramic thin films grown by HIPIMS are known to be strongly dependent on the charge state of Ti n+ (n = 1, 2, …) ions incident at the film growth surface.We find that the flux of Ti n+ with n > 2 is insignificant; thus, we measure the Ti 2+ /Ti + integrated flux ratio / at the substrate position as a function of the choice of noble gas --Ne, Ar, Kr, Xe, as well as Ne/Ar, Kr/Ar, and Xe/Ar mixtures --supporting the plasma. We demonstrate that by changing noble-gas mixtures, varies by more than two orders of magnitude with only a small change in . This allows the ratio / to be continuously tuned from less than 0.01 with Xe, which has a low first-ionization potential , to 0.62 with Ne which has a high . The value for Xe, = 12.16 eV, is larger than the first ionization potential of Ti, = 6.85 eV, but less than the second Ti ionization potential, = 13.62 eV. For Ne, however, = 21.63 eV is greater than both and . Therefore, the high-energy tail of the plasma-electron energy distribution can be systematically adjusted, allowing / to be controllably varied over a very wide range.corresponding author: grzgr@ifm.liu.se; phone: +46 13 28 1213

Strategy for simultaneously increasing both hardness and toughness in ZrB2-rich Zr1−xTaxBy thin films

“…During the time in which the synchronized substrate bias is applied, 30 to 130 µs following HiPIMS pulse initiation, the integrated Ta + intensity constitutes 91% of the total ion flux, while Ta 2+ and Ar + contribute 5 and 4%, respectively. The dominance of the Ta + signal is due primarily to strong gas rarefaction, 78,79 together with quenching of the electron-energy distribution 80 The film growth direction is along the cone-shaped sample.…”

Extended metastable Al solubility in cubic VAlN by metal-ion bombardment during pulsed magnetron sputtering: film stress vs subplantation

“…58 High doubly-ionized fraction of the sputtered metal flux can be expected if 2 < 1 , as is the case for V target sputtered in Ar/N2 gas mixture ( 2 = 14.66 eV, 1 = 15.76 eV, and 2 1 = 15.55 eV), 59 due to significant electron population with energies 2 < < Fig. 2), in a very good agreement with the previously reported value of 0.54 obtained with a DC process employing substrate rotation and significantly shorter target-to-substrate distance.…”

Time evolution of ion fluxes incident at the substrate plane during reactive high-power impulse magnetron sputtering of groups IVb and VIb transition metals in Ar/N2

“…Metal-ion-synchronized high-power pulsed magnetron sputtering (HiPIMS), 1,2 a technique developed for ion-assisted film growth, can provide additional control over layer composition and properties via significant ionization of the sputtered target atoms. 3,4,5,6,7,8 Gas rarefaction, due to the presence of high temporal metal fluxes from the sputtering target, 9,10,11,12 results in large variations in the intensities of gas-and metal-ion fluxes incident at the growing film surface during each HiPIMS pulse. 13 Thus, by employing a substrate bias potential that is synchronized with the metal-ion-rich portion of the HiPIMS pulse, metal and gas ions incident at the substrate can be separated in both the time and energy domains.…”