Oscillations and huge preferences of PbTe crystal surface sputtering under Secondary Neutral Mass Spectrometry conditions

TL;DR

This study investigates PbTe crystal sputtering by Ar plasma, revealing oscillations, large Te preference, and excess Te yields, attributed to charge state dynamics and re-deposition effects during sputtering.

Contribution

It uncovers novel phenomena in PbTe sputtering, including oscillations and large Te preference, linked to charge states and re-deposition processes, advancing understanding of sputtering mechanisms.

Findings

Aperiodical oscillations of sputtering yields observed.

Te sputtering preference exceeds two orders of magnitude initially.

Excess Te yield over Pb during prolonged low-energy sputtering.

Abstract

Sputtering of PbTe crystals by Ar plasma with ion energies 50-550 eV is investigated. A dependence of sputter yields of the Te and Pb on the sputtering ion energy and sputtering time is measured. New phenomena: aperiodical oscillations of Pb and Te sputtering; a huge preference of Te sputtering reaching more than two orders of magnitude at the beginning of sputtering process; and a significant excess of Te integrated sputter yield over that of Pb for prolonged sputtering by low energy plasma at 50-160 eV, are observed. It is substantiated that these phenomena can be caused by the peculiarities of the charge states of the interstitial Pb and Te in PbTe crystal matrix and the processes of re-deposition of sputtered atoms on the sputtered surface