Die Bestimmung von Halbleiterparametern in Ge-PIN-Detektoren mit der Elektronensonde

Summary In this paper we report the use of the scanning electron beam technique for a measurement of the ambipolar diffusion length, the surface recombination velocity and the electric field distribution in Ge-Li-PIN-Diodes. A simple relation between the diffusion length and the photovoltage induced by the electron beam is derived. The diffusion length as a function of temperature shows a strong increase with decreasing temperature. This fact limits our method to temperatures above –80°C. A measurement of the electric field distribution is demonstrated for the case of double injection in PIN-Diodes with an extended intrinsiczone. The conductivity modulation caused by the electron beam, at constant current in forward direction, results in a change in the terminal voltage which is proportional to the square of the electric field strength at the injection point.