Finite element analysis and experimental study on electrical damage of silicon photodiode induced by millisecond pulse laser

In this paper, based on the thermal elasto-plastic constitutive theory and the equivalent specific heat method, the electrical damage in the silicon-based positive-intrinsic-negative (PIN) photodiode irradiated by millisecond (ms)-pulsed laser is investigated. On condition that the internal material of the photodiode is isotropic and threelayer structure of the P-I-N satisfying temperature continuity and heat flow balance, a two-dimensional (2D) simulation axisymmetric model for silicon-based PIN photodiode irradiated by ms-pulsed laser is built. The thermal and stress field distribution are simulated in the silicon-based PIN photodiode irradiated by the Nd:YAG ms-pulsed laser at 1064 nm through using the finite element simulation software. At the same time, electrical parameters before and after the experiment of the silicon-based PIN photodiode irradiated by pulsed laser are measured. The experimental results show that the surface is melted and ablated gradually with the increase of temperature in the high energy pulsed laser, and there is a gradient change for the temperature in spatial distribution. With the increase of laser energy density, photoelectric detector shows the temperature rise phenomenon and damage effect is more obvious. When the tensile stress or compressive stress is greater than 1.7 GPa, the photosensitive surface and the silicon lattice are damaged with the changes of thermal and stress fields. Bond cleavage can change the photogenerated carrier transport channel, and the transport time can be longer. In this process, the photogenerated electron-hole pairs are readily recombined, carrier lifetime decrease and carrier concentration increase, which leads to the increase of the dark current and the decrease of the responsivity. Eventually the performance of photodetector detection is reduced. Through comprehensive comparison between experiment and simulation, one can confirm that this theoretical model has a considerable level of reliability. The conclusion we can draw is that the threshold of electrical damage is 1.7 GPa. So the control of annealing temperature is extremely important for the process of making PIN photodiode. Preventing the lattice damage of the material can improve the product yield rate. In addition, from the point of view of the use of products, the stability of the working environment can extend the service life of products, and the detection accuracy is guaranteed. Conclusively, the results in this paper establish the foundation to investigate the electrical damage mechanism in the silicon-based PIN photodiode irradiated by ms-pulsed laser.