Correcting the Characteristics of Silicon Photodiodes by Ion Implantation

Abstract

The measured electrical parameters of silicon pin photodiodes subjected to the implantation of defect-forming ions and subsequent heat treatment are analyzed, which reveal a new way of reducing the dark current and enhancing the device yield. The data of the electrical measurements are compared with the results of the structural study. The experimental efficiency of proton irradiation of the n+–p junction periphery for protecting the surface of high-resistance silicon-based pin photodiodes is experimentally established. The optimal proton irradiation and subsequent annealing regimes (an energy of E = 100 + 200 + 300 keV, a dose of D = 2 × 1016 cm–2, a temperature of T = 300°C, and a time of t = 2 h) are determined, which ensure the formation of a surface layer with characteristics optimal for obtaining the minimum dark currents of photosensitive areas and a guard ring. The use of these regimes in commercial pin photodiodes with an n+–p junction depth of ~3 μm has allowed a reduction in the dark current by an order of magnitude and an increase in the device yield.