Activation of electrical defects under Rapid Thermal Annealing in Cz-silicon for solar cells application

Boron-Oxygen related defects causes electrical degradation of the solar cells under a prolonged illumination exposure which commonly known as LID phenomena. To neutralize these defects we can use an optimized thermal treatment of the Cz–Si wafers. The aim of this work is to study the effect of the Rapid Thermal Annealing (RTA) on the optical and electrical properties of the P-type Cz–Silicon wafers destined to solar cell fabrication. Using optical microscopy we have observed a thermal stress effect on the silicon surface morphology. Fourier Transform Infrared Spectroscopy (FTIR) spectra reveal peaks corresponding to the oxygen dimers the related VOx vacancy-oxygen species like and new thermal donors (NTD) were indicating their activation during the thermal processing setup. We observe electrical degradation in the effective carrier lifetime τ _eff from 270 μs to 2 μs at a temperature peak T = 1000 °C. The results of the present work allow us to optimize the adequate RTA profile to neutralize the LID due to the BO defects without electrical degradation quality of the Cz–Si wafers. (paper)