J. Lagowski et al., IRON DETECTION IN THE PART PER QUADRILLION RANGE IN SILICON USING SURFACE PHOTOVOLTAGE AND PHOTODISSOCIATION OF IRON-BORON PAIRS, Applied physics letters, 63(22), 1993, pp. 3043-3045
The photodissociation of iron-boron pairs in p-type silicon produces l
ifetime killing interstitial iron and may be combined with noncontact
surface photovoltage (SPV) measurement of the minority carrier diffusi
on length to achieve fast detection of iron. We found that, for iron c
oncentrations ranging from 8 X 10(8) to 1 X 10(13) atoms/cm3, the pair
dissociation using a white light (10 W/cm2) was completed within 15 s
. Surface recombination was a major rate limiting factor. Passivation
of the surface enhanced the rate by as much as a factor of 20. The pho
todissociation rate increased with increasing temperature, however, th
e increase was smaller than that of the thermal dissociation rate. The
se characteristics are consistent with a previously proposed recombina
tion enhanced dissociation mechanism. For practical iron detection, it
is important that the detection limit of the approach is close to one
part per quadrillion.