Electron-Spin-Resonance Studies of Heavily Phosphorus-Doped Silicon

The paramagnetic susceptibility $\chi$ and relaxation time $T_1$ of phosphorus-doped silicon have been investigated in the temperature range between 1. 5 and 100 °K by means of 2- and 9-GHz electron-spin-resonance (ESR) methods. The temperature dependence of $\chi$ is found to be appreciable even at temperatures far below the degeneracy temperature for the samples of donor concentrations 4. 9 ∼ 16 × ${10}^{18}$ ${\mathrm{cm}}^{-3\mathrm{}}$, where the metallic-impurity conduction is observed; moreover, in these samples, ${T_1}^{-1\mathrm{}}$ shows a linear temperature dependence. From the analysis of the temperature change of ESR intensities, it is concluded that $\chi$ should be composed of two parts: a contribution of the Curie paramagnetism due to localized magnetic moments and that of the Pauli paramagnetism of conduction electrons. The donor concentration dependence of each part is in qualitative agreement with the results of the Mikoshiba's inhomogeneity model. The linear temperature dependence of ${T_1}^{-1\mathrm{}}$ is interpreted as due to the interaction between localized moments and conduction electrons, where Hasegawa's theory for dilute alloy systems is applied. The results are also compared with those of the static-susceptibility measurements.