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).

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[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).