Enhancement of Light-to-Dark Current Ratio Via Coupling Effect for MIS (p) Tunnel Diode Photo Sensors

Abstract

The current of metal-insulator-semiconductor (MIS) tunnel diodes is dependent on the Schottky barrier height and there are different mechanisms which dominate MIS tunnel currents while MIS tunnel diodes are biased at positive and negative voltages. In this work, coupled current-voltage behaviors were observed in a MIS(p) tunnel diode with a MOS structure coupled nearby (1). It was found that the MIS(p) saturation tunneling current could be controlled by the voltage bias (V G ) of the nearby MOS capacitor. While V G changes, the minority carrier distribution at the fringe of the MIS tunnel diode also changes. As a result, by wellcontrolling V G , the light to dark current ratio I light /I dark can be effectively enhanced. In this study, two intensities of illumination on MIS(p) tunnel diodes of three different oxide thicknesses were displayed. It is shown that under both intensities of illumination, the light to dark current ratio I light /I dark are all effectively enhanced by well-controlling V G . It is also found that the maxima of current ratio I light /I dark take place at different values of V G for different intensities of illumination. The coupling effect plays an important role in this phenomenon.

Photo Response Enhancement in MIS(p) Tunnel Diode via Coupling Effect by Controlling Neighboring Device Inversion Level

“…9 Metal material of aluminum was employed in this study since aluminum combining with p-type silicon could form Schottky barrier making this combination a proper candidate for sensing devices. 7…”