The effect of microlenses in photodiodes' dark current measurement

Abstract

This paper presents the influence of microlenses (MLs) in the photodiodes' (PD) dark current. A MLs array was aligned and fabricated directly on top of the PDs and their effects on the dark current was measured. Two square PDs with the sides measuring 24 and 240 mu m were evaluated under two different reverse bias voltages, 0 and -4 V. For the 24 mu m PD, when the MLs were fabricated on its surface, the dark current mean value was reduced by 35.47% and 35.42%, for 0V and -4V reverse bias voltage, respectively. In the case of the 240 mu m PD, a reduction of 14.43% and 14.42% was obtained for 0 and -4V reverse bias voltage, respectively. Moreover, the dark current measurements along the time present a more constant value with the MLs.