SIMOX characterization by photoinduced transient spectroscopy

The technique of photoinduced transient spectroscopy (PITS) has been applied to the study of deep-level traps in SIMOX (separation by implantation of oxygen) silicon ⟨100⟩ wafers with 30 Ω-cm substrate resistivity. A broadband single-pulse dye laser with a peak wavelength at 0.6 μm and 10 mJ per pulse of 1 μs duration was used to create a large excess-carrier population able to charge the traps in the silicon energy gap. The transients were measured at constant temperature in the range of 100 to 300 K and were composed of several exponential regions of different time constants. After a fast recombination period, persistent photoconductivity transients were observed with millisecond to second time constants. These transients contain information on the trap cross sections and energies as the traps return to thermal equilibrium by either emission or capture processes. Arrhenius plots are used to extract the trap parameters from these data as with conventional deep-level transient spectroscopy