Defect-Impurity Relationships in Electron-Damaged Silicon

Crucible grown p-type silicon crystals with various dopants were irradiated with 1 MeV electrons. The Hall coefficient measurements indicated that the introduction rate of the Ev + 0.3 eV energy level was independent of the chemical acceptor atoms and the dislocation density. This energy level was not found in similar float zone crystals. The evidence supports a defect complex with oxygen, but does not involve atoms of the chemical acceptor. Annealing studies of the Ev + 0.3 eV level indicated a first stage annealed at 400°C and a second stage anneal at 550°C. The second phase of this work involves the electron irradiation of heavily-doped samples of floating zone silicon. It was found that the defect introduction rate increased very slowly with phosphorus concentration. The introduction rate decreased linearly with the remaining car rier concentration during irradiation. In the impurity conduction region, the activation energy for conduction increased with electron irradiation. Production of vacancy-phosphorous pairs appears to be responsible for the changes observed.