Hydrogen-related defect centers in float-zone and epitaxial n-type proton implanted silicon

• Hydrogen-related defects in float zone (Fz) and epitaxial (Epi) n-type silicon crystals have been studied by means of deep level transient spectroscopy. These defects, as well as the characteristic vacancy-oxygen (VO) and divacancy (V-2) centers were introduced by proton implantation (1.3 MeV) using a dose of 1 x 10(10)/cm(2). A hydrogen-related defect level located at 0.45 eV below the conduction band edge (E-c) appears in both kind of samples. Another hydrogen-related defect appears predominantly in the Fz samples with a level at E-c - 0.32 eV. Depth profiling as well as annealing studies strongly suggest that the level at E-c - 0.45 eV is due to a complex involving hydrogen and V2 The level at E-c - 0.32 eV is strongly suppressed in the high purity Epi samples and the same holds for VO center. These results together with annealing data provide substantial evidence that the E-c - 0.32 eV level originates from a VO-center partly saturated with hydrogen (a VOH complex). Finally, in the Epi samples a new level at similar toE(c) - 0.31 eV is resolved, which exhibits a concentration Versus depth profile strongly confined to the damage peak region. The origin of this level is not known but the extremely narrow depth profile may indicate a higher-order defect of either vacancy or interstitial type,

Nyckelord

defects

ion implantation

hydrogen

silicon

DLTS

bombarded silicon

electron traps

vacancy

irradiation

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