Quantitative analysis of ionization rates of depositing particles in reactive plasma deposition using mass-energy analyzer and Langmuir probe

Abstract

The ionization rates of depositing particles in reactive plasma deposition (RPD) were quantitatively investigated using a measurement system composed of a mass-energy analyzer and a Langmuir probe in order to clarify the formation mechanisms of high-quality transparent conductive oxide films. The detection efficiencies of neutral particles and ions in the mass-energy analyzer were calibrated by the Langmuir probe. The species ionization rates were measured during indium tin oxide (ITO) deposition. The ionization rates associated with changes in the deposition chamber pressure were also measured. During ITO deposition, the lower limits of the following ionization rates were determined: indium ionized at a rate of 74-87%, oxygen atoms at 0.5-0.6%, and oxygen molecules at 0.01-0.02%. These rates may increase depending on the pressure in the deposition chamber. This method would also be applicable for measuring general plasma processes.

In2O3‐Based Transparent Conducting Oxide Films with High Electron Mobility Fabricated at Low Process Temperatures

“…The grain size of the films deposited at high (low) P H2O was ≈5.5 μm (≈0.81 μm), which are far larger than that (≈0.44 μm) of the films deposited via magnetron sputtering . This finding can be explained by the lower densities of crystalline nuclei in the as‐deposited films deposited via RPD because the energy (<40 eV) of depositing particles (In, O, and O 2 ) during RPD is lower than that during magnetron sputtering.…”

Tailoring of Point Defects in Polycrystalline Indium Tin Oxide Films with Postirradiation of Electronegative Oxygen Ions

“…Unlike conventional sputtering deposition, a characteristic of RPD is the use of positively charged ions with low energies, such as In + and Zn + ions, supplied by DC arc discharge; for the fabrication of ITO and ZnO films, the ion energies range from 15 to 60 eV and from 20 to 60 eV, respectively. This low-ion-energy technology allows us to fabricate high-quality oxide films with the near-bulk densities.…”

High-Hall-Mobility Al-Doped ZnO Films Having Textured Polycrystalline Structure with a Well-Defined (0001) Orientation

“…The CL comprises GZO films deposited by ion plating (IP) with dc arc discharge. The IP technique enables us with the optimization of the energy of the incident particles from the target to the substrate surface, with a high plasma density in the order of 10 12 /cm 3 resulting in high ionization rates of Zn, Ga, and O atoms, to promote the formation of the columnar grains with the highly preferential c -axis orientation owing to the well-defined (0001) orientation in the entire GZO films and to enhance high lateral diffusion of the above species leading to the films exhibiting the flat surface [ 19 , 20 ]. The CLs play a critical role in achieving the AZO films having a textured polycrystalline structure with a well-defined single (0001) orientation.…”