A SIMS study on positive and negative ions sputtered from graphite by mass-separated low energy Ne+, N-2(+) and N+ ions

Authors
Citation
Zw. Deng et R. Souda, A SIMS study on positive and negative ions sputtered from graphite by mass-separated low energy Ne+, N-2(+) and N+ ions, NUCL INST B, 183(3-4), 2001, pp. 260-270
Citations number
39
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Spectroscopy /Instrumentation/Analytical Sciences","Instrumentation & Measurement
Journal title
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS
ISSN journal
0168-583X → ACNP
Volume
183
Issue
3-4
Year of publication
2001
Pages
260 - 270
Database
ISI
SICI code
0168-583X(200110)183:3-4<260:ASSOPA>2.0.ZU;2-5
Abstract
Temperature effect on positive and negative ion yields sputtered from graph ite by low energy Ne+, N-2(+) and N+ ions was studied using a special mass- separated low energy ion beam system and secondary ion mass spectrometry (S IMS) measurements. The origin of dominant positive and negative ions was di scussed according to the obtained temperature effect. It was found that Cion emission was enhanced by nitrogen ion bombardment compared with Ne+ bom bardment and decreased to the same level as Ne+ bombardment at elevated tem perature. The enhancement effect was attributed to adsorption or deposition of nitrogen to form weakly bound Cdelta+-CNdelta- species on the surface. No chemical enhancement effect was observed on C, emission during nitrogen ion bombardment. The C, yield increased with temperature during Ne+ and nit rogen ion bombardment and was assigned to originate from carbon network of graphite as a consequence of physical sputtering. During nitrogen ion bomba rdment. CN ions dominated both the positive and negative ion emission. CN i on yield during 800 eV N-2(-) and N+ bombardment decreased at elevated temp erature, whereas during 100 eV N-2(+) bombardment, it increased with temper ature. CN- yield as a function of kinetic energy of primary ions also exhib ited difference from that of C+ and C-2(-). Three possible channels for CN- emission have been proposed. At higher primary energy (several hundred eV and above), physical sputtering can partly account for CN- emission. At low er primary energy (below 100 eV), it is attributed to chemical etching of s urface carbon atoms by energetic nitrogen atoms and ion-induced desorption of CN species. (C) 2001 Elsevier Science B.V. All rights reserved.