Calibration Relationships for Optically Measuring the Concentrations of Boron, Gallium, and Indium in Silicon.
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
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New, more effective calibration relationships have been experimentally determined which enable FTIR absorption spectroscopy to accurately measure the impurity concentrations of In, Ga, and B in silicon. The peak areas of the Group III acceptor related spectra, are shown to behave linearly with concentration 13 or concentration 23, rather than simply being proportional to concentration as was previously assumed. These calibration relationships were determined for optical measurements made on samples cooled to 5K for In and Ga, and to 5-8K for B. The relationships for some lines of Ga and In were tested and found to still be accurate for sample temperatures up to 9K. From the high resolution optical measurements made in this study, previously unobserved acceptor related spectral lines were seen. These new lines were observed in the P32 spectra of In, Ga, Al, and B. Also a 5p was observed in the P12 spectra of Ga. A feature in each acceptors P32 spectrum is defined as EI, the ground state binding energy, and the spin-orbit splitting of the silicon valence bands was measured. All the IR induced excited states of In, Ga, Al, and B were measured. After renumbering of the B lines 5 - 11, a more complete correspondence between all the Group III excited state lines was shown than any published previously.
- Atomic and Molecular Physics and Spectroscopy
- Solid State Physics