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Why are phosphorus, arsenic, and antimony impurities in silicon and germanium studied by ESR?

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magnetic resonance Figure 1: Precession of a magnetic dipole moment μ in the presence of a constant field H and a rotating field H′ (see text)

Phosphorus, arsenic, and antimony are studied in silicon and germanium using electron-spin resonance (ESR) because they act as dopant atoms that modify the electrical conductivity of these semiconductors.21

When these impurities are substituted into the crystal lattice of silicon or germanium, they function as donor atoms, providing an extra electron for electrical conduction. ESR is a powerful tool for investigating these centers because the magnetic moments of such impurities typically exhibit the characteristics of a free electronic spin.12

By analyzing the hyperfine and superhyperfine structure observed in ESR spectra, researchers can map the electronic magnetization and obtain detailed, quantitative information regarding the status and environment of these impurities within the semiconductor material. This process allows for a rigorous test of the microscopic models used to describe such defects.2