Non-local aspects of breakdown in pin diodes

Abstract

Measurements of breakdown voltage in p-i-n diodes with thin i regions are compared with local and non-local theoretical calculations. It is found that overshoot effects compensate for the dead space at high fields close to breakdown but that non-local aspects become stronger at lower fields.

The merits and limitations of local impact ionization theory [APDs]

“…In the devices even thinner than 0.2 m, the local model overestimates the multiplication at low bias values but the difference decreases with increasing bias so that the local model gives good agreement with the measured breakdown voltage, , for the entire range of device widths. Agreement between the local model and measured for p -i-n sdownto m thick was reported previously by Milledge et al [15].…”

“…1. Consequently, the agreement between the data of Milledge et al [15] and our measurements in Fig. 1 only indicates good agreement between measured values.…”

“…1. This apparent anomaly can be understood by noting that the local ionization coefficients of [15] which are used in these calculations were deduced from the measured of m and mp -i-n s with very similar electric field profiles to those we measured and showed in Fig. 1.…”

“…For the local calculation the values of and were taken from Bulman et al [6] for electric fields, , up to 500 kV/cm since this investigation involved measuring both the multiplication and excess noise characteristics of several samples with overlapping field regions and represents the most extensive and rigorous to date. For kV/cm, the of Milledge et al [15] was used and it was assumed that since our experimental results in [14] showed and become indistinguishable in thin structures. In this work, we continue to use these two sets of parameters for the coefficients since they enable the data to be more accurately quantified over …”

Avalanche noise characteristics of thin GaAs structures with distributed carrier generation [APDs]

“…The values of and are found from the relationships [10] (3a) (3b) and the experimental ionization coefficients, and . These are taken from the work of of Bulman et al [11] for kV/cm, and from the work of Millidge et al [12] for kV/cm with set equal to . and are interpolated around kV/cm to produce a smooth transition from the data of Bulman to Millidge.…”