Damage of InP (110) induced by low energy Ar+ and He+ bombardment

Plasma-induced surface damage of a III-V compound semiconductor, a problem associated with many device fabrication processes, is clarified with carefu l measurements of surface defect density induced by low energy ion bombardm ent of InP. In the study, n- and p-InP (110) surfaces were prepared by clea vage of InP in ultrahigh vacuum, and then bombarded as a function of ion ty pe (He+ and Ar+), energy (5-100 eV), and fluence (10(12)-10(17) ions/cm(2)) . The dynamic process of surface Fermi level shifting induced by such bomba rdment was determined by in situ high-resolution x-ray photoelectron spectr oscopy, and the data were then converted to information on surface defect f ormation. It was found that both He+ and Ar+ bombardment with the above con ditions moved the Fermi levels of both n- and p-InP (110) surfaces towards 0.95 eV above the valence band maximum of InP. As expected, for the same bo mbardment energy, Ar+ caused more damage than He+, and for the same ion typ e, the bombardment induced a surface defect density. increasing with both i on energy and fluence. It was also found that the threshold condition for d efect formation was a combined function of the impact energy of the incomin g ion and the energy released during its neutralization. (C) 2000 American Vacuum Society. [S0734-2101(00)02105-9].