Negative Capacitance on Silicon Avalanche Photodiodes with Deeply Buried Micropixels

Abstract

There have been investigated reactive properties of silicon avalanche photodiodes (MAPD- Micropixel Avalanche Photodiode) with deeply buried micropixels (amplification channels) within AC signal frequencies f= (50-500) kHz.By experiment is found out that measured capacitance of structures involving three p-n junctions in section passing through the pixels increases exponentially with Ufor (negative potential is applying to n-Si substrate) reaches maximum and at certain value Ufor= Uinv changes the sign becoming the negative capacitance (equivalent inductance).The magnitude of active component of complete conduction G grows with the applied voltage and reaches maximum value ~70 mS at Ufor= 1,0 V (f=500 kHz). There has been calculated difference in phase j appearing between current and voltage and it is shown that at Ufor=0 V the j = 80o and passes through the zero at Ufor = 0,55 V. The magnitude of negative capacitance recalculated to the inductance value with the growth of forward bias being decreased sharply tends to the saturation.