https://doi.org/10.15407/iopt.2019.54.051

Optoelectron. Semicond. Tech. 54, 51-78 (2019)

A.V. Sukach, V.V. Tetyorkin, A.I. Tkachuk, S.P. Trotsenko, M.Yu. Kravetskii, I.M. Matiyuk, A.V. Fedorenko

InSb Photodiodes (Review. Part V)

The most important procedures for production of diffusion InSb p-n junctions are analyzed – the cadmium diffusion and its solubility in InSb, the passivation of the active region of photodiodes and methods for its implementation. It is shown that the cadmium diffusion in InSb are satisfactorily approximated by the expression D = 1.2 10-4exp(-1.2/kT) cm2/s in the temperature range 350-450 °C. The literature data of two methods of passivation of the active region of InSb photodiodes - the formation of anode films and surface sulfidation, which lead to a decrease in surface current, are analyzed. The data are systematized on technological operations of mechanical and chemical surface treatment of InSb substrates, which are used for the production of diffusion p-n junctions. The technological routes of mechanical, chemical-mechanical and chemical-dynamic surface treatment of InSb substrates are given, which minimize the thickness of the damaged layer, and also stoichiometerize the surface of the substrates during chemical treatments.

The influence of surface conductivity on the electrical properties of mesostructured InAs p-n junctions made by Cd diffusion is investigated. It was found that the use of 2% Br2+HBr etching solution for manufacture of mesostructured p-n junctions leads to the appearance of surface shunt conductivity. The second chemical treatment of mesostructures in nitric acid-based solution significantly reduces the dark current and the effect of shunt conductivity on the I-U characteristics. It is shown that the dark current in p-n junctions after repeated chemical treatment of mesostructures is determined by the generation and recombination of carriers in the depletion region for the temperature range of 160-298 K, and tunneling of carriers at temperatures below 160 K.

Keywords: InSb photodiode, cadmium diffusion, p-n junction, InSb substrates, passivation, sulfidation, shunt current.