Ion Velocity Distribution Function Effects on Atomic Layer Etching in a RF Discharge

RF Discharges are used in a range of systems with notable applications in semiconductor processing [1], surface treatment [2], medicine [3], and water purification [4]. In this work, we model RF discharges through 1D PIC simulations and measure ion velocity distribution functions (IVDF) at the surface of a substrate immersed within the plasma. We implement the resulting IVDFs into molecular dynamics (MD) simulations to more accurately study substrate etching [5]. We discuss differences between our MD results and prior MD simulations which assumed a delta function IVDF of incident ions. Our analysis considers various plasma compositions (eg. argon) and substrate materials (eg. silicon).

[1] W. R. Harshbarger, R. A. Porter, T. A. Miller, and P. Norton, Appl Spectrosc 31, 201 (1977).

[2] P. D. Davidse, Vacuum 17, 139 (1967).

[3] D. B. Graves, J. Phys. D: Appl. Phys. 45, 263001 (2012).

[4] P. J. Bruggeman, et al., Plasma Sources Sci. Technol. 25, 053002 (2016).

[5] J. R. Vella, D. Humbird, and D. B. Graves, Journal of Vacuum Science & Technology B 40, 023205 (2022).