Effect of Structural Defects on Parameters of Silicon Four-Quadrant p-i-n Photodiodes

Abstract

The article examines the influence of structural defects, in particular dislocations, on the electrical and photovoltaic properties of silicon four-quadrant p-i-n photodiodes. It was established that growth defects and defects formed during mechanical processing of plates can cross the entire substrate and deteriorate the parameters of photodiodes. This phenomenon is particularly negative due to the placement of defects in the space charge region. In this case, due to the presence of recombination centers in the space charge region, the life time of minor charge carriers decreases and the dark current and responsivity of photodiodes deteriorate. Often, the placement of defects is uneven, which provokes unevenness of parameters on responsive elements. It was also seen that the dislocation lines crossing the responsive elements and the guard ring worsen the insulation resistance of the specified active elements. A method of determining the final resistivity of silicon and the diffusion length of minor charge carriers by studying the pulse shape of the output signal is proposed.

Keywords

• silicon
• photodiode
• point defects
• dislocations
• dark current
• sensitivity