Photo detector junction properties and dynamic aptness analysis — Computational study

As a lower band edge material application of Si photodiode as detector; reverse biasing impacts on its carrier drift or sensing speed, junction capacitance as well as its operating bandwidth. The variation of n-doping also ensures the variation of reverse breakdown voltage. In this paper we analyze the effect of n-doping profile (body doping) and the reverse voltage effect on Si photo device characteristic parameters such as depletion capacitance-junction width (JW), generation rate, operating bandwidth and gain as well. Whenever body doping concentration is increased it reduces the reverse break down voltage, as a result effective JW is decreased and capacitance is found to be increased consequently reduces the operating bandwidth and sensing speed.