THERMAL IONIZATION ENERGY OF LITHIUM AND LITHIUM-OXYGEN COMPLEXES IN SINGLE-CRYSTAL SILICON

Recent optical studies[1, 2] have found that for float-zone crystals, having a relatively low oxygen content (less than 1016 cm-3), the ionization energy of the lithium impurity was about 32 meV, whereas for pulled-crucible crystals, having a higher oxygen concentration (approximately 1018 cm-3), the ionization energy was 39 meV. Previous measurements by means of Hall effect studies had indicated that the ionization energy in a pulled crucible sample was about 33 meV which seemed to agree with the optical float-zone value. In an attempt to clarify the situation, Hall effect measurements were made on pulled-crucible and float-zone silicon samples containing lithium as an impurity, and ionization energies were calculated. It was found that this new Hall effect data seemed to be in agreement with the optical data, the ionization energy being 37 meV for the pulled crucible sample and 29.5 meV for the float-zone. © 1969.