New methods of measuring photoelectric parameters of silicon

Members of group:

• O.G. Koshelev
  

Research activity:

In the last years we have developed new methods of measurement of the photoelectric parameters of silicon wafers used for solar cell fabrication. The methods are based on compensation of the a.c. photovoltage, and are used to determine the diffusion length and the minority charge lifetime in the substrate.
One of the methods permits to determine the photoelectric parameters of wafer without conductive electrodes. In particular, it can be used for wafers packed in hermetically sealed polyethylene parcels. This allows to avoid its contamination during the measurements. The method can also be used to test the diffusion length in the wafers at intermediate stages of fabrication of solar cells and other semiconductor devices. This enables to reject nonconditional wafers in the process of fabrication and thus decrease the cost of the device. The method can be easily automatized.
The methods were tested on silicon solar cells irradiated by fast particles.

Selected publications:

• O.G. Koshelev, S.A. Lagutkin and T.B. Pleskacheva. The use of heavily doped silicon in a bolometer having a separated target. Sov.J.Opt.Technol. 52, 517 (1985).

• O.G. Koshelev, T.B. Pleskacheva and L.N. Khitrova. Transmission spectra of thin doped layers of silicon on a high-resistance substrate in the long IR region. Opt. and Spectrosc. 60, 466 (1986).

• O.G. Koshelev and T.B. Pleskacheva. Determination of the electrophysical parameters of a highly doped silicon layer on a high-resistance substrate from transmission of the layer for long-wave infrared radiation. Moscow University Physics Bulletin 43, N 1, 82 (1988).

• V.A. Morozova, O.G. Koshelev and V.V. Ostroborodova. Peculiarities of the photoelectric properties of highly pure silicon. Vestnik Moskovskogo Universiteta. Ser. Fiz., astron. 31, 92 (1990).

• O.G. Koshelev and I.V. Mikhailov. A phase method for defining the life time of minority charge carriers in the base of photoconverter. Appl.Sol.Energy 29, N 4, 11 (1993).

• O.G. Koshelev, V.A. Morozova, E.Yu. Barinova, G.M. Grigorieva and E.H. Tkacheva. Measurement of short lifetimes of minority charge carriers in silicon solar cells irradiated by fast electrons. Moscow University Physics Bulletin 48, N 4, 80 (1993).

• O.G. Koshelev and V.A. Morozova. A method of determination of photoelectrical properties of minority charge carriers in substrates of diode structures. Patent of Russia N 2019890 (1994).

• O.G. Koshelev, V.A. Morozova. A nondestructive method for measuring the photoelectric parameters of wafers with p-n-junctions. Solid-State Electronics 39, 1379 (1996).