An upgraded TOF-SIMS VG Ionex IX23LS: Study on the negative secondary ion emission of III–V compound semiconductors with prior neutral cesium deposition

• Published in: Applied surface science 2012-01, Vol.258 (7), p.2490-2497
• Main Authors: Ghumman, C.A.A., Moutinho, A.M.C., Santos, A., Teodoro, O.M.N.D., Tolstogouzov, A.
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Deposition; Electronegativity; Exact sciences and technology; Gallium arsenide; Gallium arsenides; III–V semiconductors; Indium antimonides; Indium phosphides; Ionization; Neutral cesium deposition; Physics; Secondary ion yield enhancement; Semiconductors; TOF-SIMS; Work function
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2011.10.079

► Newly developed data acquisition and control system for TOF-SIMS VG Ionex IX23LS. ► Neutral Cs deposition onto surface of III–V semiconductors prior to SIMS analysis. ► Surface cesiation enhances the peak intensity of all negative ion species. ► An enhancement is larger for In-based than for Ga-based compounds. ► The greater bond ionicity of In-based compound is responsible for such an enhancement. A TOF-SIMS VG Ionex IX23LS with upgraded data acquisition and control system was used to study the secondary emission of negative atomic and cluster ions of non-metallic elements (P, As and Sb) upon a 19keV Ga+ bombardment of non-degenerated III–V semiconductors (GaP, GaAs, GaSb, InP, InAs and InSb) with prior neutral Cs deposition from a getter dispenser. It was found that surface cesiation enhances the peak intensity of all negative ion species; in the case of atomic ions, the greatest increase (360) was observed for P− emitted from InP. Such an enhancement was larger for In-based than for Ga-based compounds. We explained that in terms of an electronegativity difference between the composing atoms of III–V semiconductors. The greater electronegativity difference (bond ionicity) of In-based compounds resulted in the greater Cs-induced work function decrease leading to a higher increase in the ionization probability of secondary ions.