The influence of edge effects on the determination of the doping profile of silicon pad diodes

Edge effects for square p
⁺
n pad diodes with guard rings fabricated on high-ohmic silicon are investigated. Using capacitance-voltage measurements of two pad diodes with different areas, the planar and the edge contributions to the diode capacitance are determined separately and the doping profile is determined. The results with and without edge corrections differ significantly. After edge corrections, the bulk doping of the pad diodes is found to be uniform within ± 1.5 %. Edge corrections are determined both for non-irradiated diodes and for diodes irradiated by a fluence of 2.4-10
¹⁵
n
_eq
/cm
²
24 GeV/c protons. The edge correction for irradiated diodes is found to be larger than for non-irradiated ones.