Oxygen-Related Donors Formed at 600 °C in Silicon in Dependence on Oxygen and Carbon Content

Results of Hall effect measurements and ir measurements at room temperature are given on the relation between donor formation and oxygen precipitation in Czochralski-silicon samples with different oxygen and carbon concentrations heat treated at 600 °C in N2 ambient. The influence of a pre-heat treatment at 450 °C is described, as well the partial destroying of 600 °C-oxygen related donors due to heat treatment at 900 °C. Donor formation at 600 °C is characterized by reaching a saturation concentration, which cannot be explained only by differences in initial [Oi]O and [Cs]O, respectively. The formation rate (dND/dt)i for the start phase can be described approximately by (dND/dt)i = a[Oi]n with n ≈︁ 4.5 for samples with 1016 < [Cs]O < 1017 cm−3. A short heat treatment at 900 °C for 20 min after pre-heat treatment at 600 °C for 240 h caused a significant decrease of donor concentration and an increase of [Oi]. It is shown that carbon influences strongly the formation and destroying process of 600 °C-oxygen-related donors. The experimental results obtained are discussed assuming the formation of (C, O)-complexes as nuclei for oxygen cluster. In the initial phase of oxygen clustering donors should be formed.