Electronic recombinations and ionic transport in BPSG layers

Thermally stimulated luminescence (TSL) and current (TSC) measurements above room temperature were performed on 1150 nm borophosphosilicate glass films obtained by sub-atmospheric chemical vapour deposition. Several concentrations of B and P ions were considered, in the range 2-5% and 4-9% in weight, respectively. A TSC peak of ionic character at 90 deg C was observed without prior X-irradiation, followed by a monotonically growing signal. Upon X-irradiation, broad TSL and TSC signals extending from 50 to 300 deg C were detected: the intensities of both the ionic peak and the radiation induced TSL and TSC signals increase by increasing the phosphorus content, while they decrease on boron increase. The TSL emission spectrum features two bands peaking at 2.5 and 2.85 eV and a minor component at around 3.2 eV. On the basis of these data, the dynamics of ionic carriers and electronic traps in BPSG layers are discussed.