Stopping power dependence of nitrogen sputtering yields in copper nitride films under swift-ion irradiation: Exciton model approach

Abstract

Nitrogen sputtering yields as high as 10 4 atoms/ion, are obtained by irradiating N-rich-Cu 3 N films (N concentration: 33 ± 2 at.%) with Cu ions at energies in the range 10-42 MeV. The kinetics of N sputtering as a function of ion fluence is determined at several energies (stopping powers) for films deposited on both, glass and silicon substrates. The kinetic curves show that the amount of nitrogen release strongly increases with rising irradiation fluence up to reaching a saturation level at a low remaining nitrogen fraction (5-10%), in which no further nitrogen reduction is observed. The sputtering rate for nitrogen depletion is found to be independent of the substrate and to linearly increase with electronic stopping power (S e ). A stopping power (S t j,) threshold of ~3.5 keV/nm for nitrogen depletion has been estimated from extrapolation of the data. Experimental kinetic data have been analyzed within a bulk molecular recombination model. The microscopic mechanisms of the nitrogen depletion process are discussed in terms of a non-radiative exciton decay model. In particular, the estimated threshold is related to a minimum exciton density which is required to achieve efficient sputtering rates.

Observation of the Direct Energy Band Gaps of Defect-Tolerant Cu3N by Ultrafast Pump-Probe Spectroscopy

“…Cu 3 N has been obtained by a variety of methods including sputtering, ,− molecular beam epitaxy, atomic layer deposition, , and pulsed laser deposition. , Recently, Matsuzaki et al have obtained Cu 3 N from Cu under NH 3 and O 2 between 500 and 800 °C. However, in the past, most have obtained Cu 3 N by sputtering of Cu under N 2 in conjunction with Ar, which enables control over its stoichiometry.…”

Alternative approaches to electronic damage by ion‐beam irradiation: Exciton models

“…The lattice breakdown starts forming nitrogen molecules than migrate through the lattice and escape from the material (atom sputtering). In fact, high sputtering rates have been measured for thin Cu 3 N films that are an increasing function of electronic stopping power, Fig. .…”

“…Initial rate of nitrogen sputtering yield y as a function of electronic stopping power for Cu 3 N films deposited on glass (open squares) and Si (open circles). The predictions from the exciton model are included as diamonds .…”

Ion beam effects of 26.0 MeV Cu 7+ ions in thin metallic and insulating films during Heavy Ion ERDA measurements

“…al. [14], not much else has been reported. This latter energy region is where most small accelerator labs involved in heavy ion Time-of-Flight (ToF) ERDA operate [9,[15][16][17][18][19][20].…”