Analysis of the product in and photodiodes

Abstract

The effect of the layer in a structure made in long-wavelength (x = 0.229) epilayers on the zero-bias resistance - area product is theoretically analysed, and compared with a structure. A step profile is assumed for the concentration in the and layers, fabricated by ion implantation and annealing. Various current components (diffusion currents in the , and p layers, depletion layer and surface generation - recombination (g - r) currents, band-to-band and trap-assisted tunnelling) are taken into account. The effect of the surface recombination velocities, and the concentrations (p-side trap, layer, and p layer) are discussed in detail. The results of this model clearly indicate the conditions under which a diode can perform better than a diode. In broad terms, a structure is more suitable for p-type epilayers with lower trap concentrations and higher lifetimes, whereas a structure is advantageous, in terms of increasing , for higher trap concentrations and lower lifetimes. Another advantage of the structure is that reduced tunnelling implies that a higher acceptor concentration can be accepted for device fabrication.