E. D. van Hattum

On the ion and neutral atom bombardment of the growth surface in magnetron plasma sputter deposition

The energy distribution of positive argon ions bombarding the substrate during radiofrequency magnetron sputter deposition has been measured as a function of the argon pressure. The results are related to measurements of the plasma potential distribution and understood invoking the occurrence of resonant charge transfer reactions. This effectively lowers the ion bombardment energy and causes the bombardment of the growth surface with neutrals of a few eV kinetic energy in the pressure range of 0.1–1Pa.

Characterization of the plasma in a radio-frequency magnetron sputtering system

In order to understand the fundamental mechanisms in a radio-frequency magnetron sputtering system, the main properties of the argon plasma used in the process have been measured. A complete three-dimensional map of the ion density, electron temperature, and plasma potential has been obtained using a Langmuir probe. The electron temperature as well as the ion density have been found to increase in the region of the so called race track at the cathode. Furthermore, from the plasma potential map, the time-averaged local electric field has been obtained, pointing out the race track as the region where the most intense ion bombardment takes place. Besides, only the ions produced near the race track are accelerated towards the cathode, whereas those produced in the remaining volume move towards the anode. Finally, the dependence of the plasma quantities on the incident radio-frequency power and deposition pressure has been studied. The plasma potential measured using the Langmuir probe has been found to agree ...

Characterization of a low-pressure argon plasma using optical emission spectroscopy and a global model

The excitation mechanisms of the lower lying excited levels in a low-ionized, low-pressure, argon plasma are modeled and studied in order to characterize the plasma through optical emission spectroscopy. It is found that the lower lying excited states of argon play an important role in the excitation and that they must be taken explicitly into account for an accurate determination of the excitation rates. The possible influence of radiative cascades from upper argon excited states, which are not included in the model, has been studied by introducing an effective level in the description and studying its influence on the results. The model has been used to calculate the electron density and electron temperature in an argon magnetron sputtering plasma produced at different electromagnetic powers and gas pressures, as a function of the intensity of the optical emission lines λ1=750.38nm and λ2=696.54nm. The results obtained from the model have been compared with Langmuir probe measurements, showing a good ag...

Distinct processes in radio-frequency reactive magnetron plasma sputter deposition of silicon suboxide films

A detailed investigation of the distinct processes in radio-frequency reactive magnetron plasma sputter deposition of SiOx films in a O2∕Ar atmosphere has been carried out, using the experimental evaluation of the individual growth rates of silicon and oxygen and of the ion impingement on the growth surface. Experimental variables are the total pressure, the oxygen partial pressure necessary to grow layers with 0⩽x⩽2, the RF power, the substrate temperature during deposition and the height of the cathode with respect to the growth surface. The various possible contributions to the silicon and oxygen incorporation on the growth surface have been distinguished and the magnitude of their contribution estimated, including that of sputtered SiO molecules. A model concerning the oxygen coverage on the cathode erosion area during sputtering is discussed, including the transition from the metallic cathode to the poisoned, nonmetallic, cathode.