Manifestation of clustering of Ge atoms in the spectra of electron spin resonance of Si1 − x Ge x alloys (0 < x < 0.057)

The electron spin resonance (ESR) at phosphorus dopants in the P-doped Si1−x Ge x alloys (0 < x < 0.057) with the concentration of phosphorus in the range 1015–1016 cm−3 is studied at temperatures from 3 to 30 K. The ESR spectra of the alloys (x > 0) are compared to the ESR spectra of similar silicon samples (x = 0). It is found that, from the smallest Ge content x = 0.008, the ESR spectra contain two additional lines. It is assumed that these lines are due to phosphorus dopants located in clusters with higher Ge content. It is found that an increase in the Ge content in the alloys up to x = 0.024 yields only an increase in the concentration of such clusters. At x ≥ 0.024, the Ge content increases with x both inside and outside the clusters.