Calculation of tunneling currents in (Hg,Cd)Te photodiodes using a twosided junction potential
Abstract
It has been shown previously that tunneling current can become the dominant dark current and hence the performancelimiting factor in diodes formed in narrow bandgap semiconductors, such as Hg(1x)Cd(x)Te. In this paper, a calculation is conducted of the tunneling current using a Kane approximation for the nonparabolic conduction band and a more realistic junction potential than has been used previously. The potential used here is characteristic of a linearly graded ntype region intersecting a uniformly doped ptype region and is a better approximation to the actual potential in a diode formed by ion implantation into a ptype substrate. It is shown that significant errors sometimes arise when the abrupt junction model is used to calculate tunneling current in these structures. The effect of changes in base carrier concentration and nside donor gradient is shown for x between 0.196 and 0.400, which corresponds to a photodiode spectral cutoff in the important 3 to 14micron region.
 Publication:

IEEE Transactions on Electron Devices
 Pub Date:
 March 1984
 DOI:
 10.1109/TED.1984.21517
 Bibcode:
 1984ITED...31..292B
 Keywords:

 Ion Implantation;
 Junction Diodes;
 Mercury Cadmium Tellurides;
 Photodiodes;
 Tunnel Diodes;
 VoltAmpere Characteristics;
 Carrier Density (Solid State);
 Conduction Bands;
 Electric Potential;
 Electrical Resistance;
 Energy Gaps (Solid State);
 Infrared Detectors;
 PN Junctions;
 Electronics and Electrical Engineering