Electron-beam generated ExB plasmas and their applications: user and host team research projects at Princeton Collaborative Research Facility*

There is a growing interest in the use of electron beam (e-beam) generated low temperature plasmas for materials processing at atomic scale with applications to microelectronics [1] and quantum systems [2]. For these applications, the plasma (electron density ~ 10⁹-10¹² cm^-3 and electron temperature ~ 0.1-10 eV) is typically generated by injecting an energetic (10² – 10⁴ eV) electron beam into a low pressure (10^-1-10² mtorr) background gas along the applied magnetic field (10-10³ Gauss). The magnetic field helps to confine e-beam propagating through the reactor/source. In addition, the applied electric field across the magnetic field enables to control the ion flux across the magnetic field. The ability of these e-beam plasma sources with crossed electric and magnetic (ExB) fields to maintain a selective production of ions and reactive species while maintaining a spatially uniform flux of low energy particles across the magnetic field to large-area substrates (e.g. wafer) placed in the periphery of the plasma makes them attractive for low damage processing of materials. In this talk, we will briefly overview several theoretical, experimental and computational studies conducted at the Princeton Collaborative Research Facility (PCRF). Focus of these studies were on electron and ion kinetics of e-beam plasmas [3] beam-plasma instabilities (e.g. in Ref. [4]), plasma-chemistry [5] and applications for gentle processing of 2D materials [6] and diamond for quantum systems [2].

References

[1] S. G. Walton et al., ECS J. Solid State Sci. Technol. 4 N5033 (2015)

[2] [5] C. Pederson et al., Phys. Rev. Mater. 8, 036201 (2024)

[3] N. S. Chopra et al., Appl. Phys. Lett. 124, 064101 (2024).

[4] H. Sun et al., Phys. Rev. Lett. 129, 125001 (2022)

[5] S. Yatom et al., Plasma Sources Sci. Technol. 32, 115005 (2023)

[6] F. Zhao et al., Carbon, 117, 244 (2021)