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

TL;DR

This paper investigates how edge effects influence doping profile measurements in silicon pad diodes, demonstrating the importance of edge correction for accurate doping concentration determination.

Contribution

It introduces a method to separate planar and edge contributions in capacitance measurements, improving doping profile accuracy in high-ohmic silicon diodes.

Findings

Edge effects significantly affect doping measurements.

Edge correction leads to more accurate doping profiles.

Bulk doping is uniform within +/- 1.5% after correction.

Abstract

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. It is shown that the doping concentration derived from the capacitance-voltage measurements with and without edge corrections differ significantly. After the edge correction, the bulk doping of the pad diodes is found to be uniform within +/- 1.5%. The voltage dependence of the edge capacitance is compared to the predictions of two simple models.