Simulation of the Metal-Semiconductor-Metal photodetector based on InAlAs/GaAsSb for the photodetection at the wavelength 1.3 µm

In this paper we present the simulation of the planar Metal-Semiconductor-Metal photodetector (MSM-PD) of interdigitated structure based on InAlAs/GaAsSb adapted for photodetection at the wavelength 1.3 μm. We use theoretical models to plot the variations of the dark current, the photocurrent, the capacity, and the cut-off frequency of the photodetector as a function of bias voltage and the different geometrical parameters. The obtained results show a very low dark current of 30-100 pA, observed at the bias voltage of 10 V, this is mainly due to the introduction of a thin layer to increase the Schottky barrier, based on In_0.52Al_0.48As in the epitaxial structure of the component. The obtained photocurrent and cutoff frequencies are very appreciable, these latter exceed the value of 2 THz for a photodetector having an active surface of 1 × 1 μm² and an interelectrode distance of 0.03 μm, and they are mainly limited by the transit time of the photo-generated carriers, given the low component capacity obtained by simulation.