The pulsed MOS capacitor generation lifetime technique was used to determine the Fe density in B-doped wafers. Effective generation lifetimes were deduced from Zerbst plots that were made of measured capacitance versus time data. Upon heating (200C, 300s), and quenching to 23C, Fe-B pairs dissociated into interstitial Fe plus substitutional B. The post-heating effective generation lifetime decreased immediately upon heating. With increasing elapsed time (increased pairing time) after Fe-B dissociation, the effective generation lifetime increased because the Fei re-formed Fe-B pairs. It required some 4 times the time-constant, for the Fe-B pairing reaction, before the post-heating effective generation lifetime returned to the pre-heating value. An expression was developed for the determination of the Fe density. The density which was obtained from this expression exhibited a good agreement with that measured by means of deep-level transient spectroscopy.

Iron Contamination in Silicon Wafers Measured Using a Pulsed MOS Capacitor Generation Lifetime Technique. S.E.Tan, D.K.Schroder, M.Kohno, M.Miyazaki: IEEE Transactions on Electronic Devices, 2000, 47[12], 2392-8