Effect of illumination positioning on the characteristics of an In0.53Ga0.47as interdigitated lateral PIN photodiode

The interdigitated lateral p-i-n photodiode (ILPP) based on In0.₅₃Ga_0.47As absorbing layer is an attractive alternative device to be used in optical communication networks operating at 10 Gbps or lower. Its simple fabrication methodology utilizing diffusion/ion implantation to form the p+ and n+ regions is a cost-reducing technique versus those used in developing conventional p-i-n photodiodes. A three-dimensional model of this device was developed and the device achieved dark currents of 0.21 nA, responsivity of 0.56 A/W, external quantum efficiency of 44 %, -3dB frequency of 8.93 GHz and signal-to-noise ratio, SNR of 36 dB at an operating voltage of 5 V, lambda=1.55 mum and P=10 Wcm^-2. Another significant advantage of the ILPP device is that it can be illuminated from three different angles; ie from the surface, from the edge and also from the bottom. In this paper, we attempt to compare the impact of optical beam illumination positioning on the common device characteristics.