Infrared absorption spectra for B- and P-alloyeda-Si: Effects of annealing

The effects of isochronal annealing on the infrared and far-infrared spectra of very heavily B- and P-dopeda-Si(H) are reported. Upon annealing, the B-H stretching mode evolves into two bands centered at 2475 and 2370cm^–1. The broad band of the heavily B-doped samples between 600 and 900cm_-1 is resolved into three peaks or absorption shoulders located at 830, 725, and 630cm_-1. The 640cm_-1 band of the heavily P-doped samples splits into two peaks centered at 630 and 670cm_-1. The assignment of the above peaks is discussed. The intrinsic infrared absorption due to the Si lattice modes changes only little as a result of the annealing. These changes are a measure of the H-induced ir activity of the Si-Si bands.