METHOD FOR MEASURING A SEMICONDUCTOR STRUCTURE, WHICH IS A SOLAR CELL OR A PRECURSOR OF A SOLAR CELL

摘要

The invention relates to a method for measuring a semiconductor structure, which has an emitter and a base, and which is a solar cell or a precursor of a solar cell, comprising the following steps: A) Generating luminescence radiation in the semiconductor structure, and spatially resolved measuring of the luminescence radiation emitted by the semiconductor structure, wherein a first measurement is conducted under a first measurement condition a, and depending on the measurement data that are obtained at least from the first measurement, a first spatially resolved, voltage-calibrated image V a (xi) for a plurality of local points xi of the solar cell is determined from the measurement data obtained in step A; B) Determining spatially resolved properties of the semiconductor structure with respect to the spatially resolved dark saturation current j 0 (x i ), and/or the spatially resolved emitter layer resistance p(x 1 ),and/or the spatially resolved, local series resistance Rs(xi) for the plurality of local points xi, depending on at least the first voltage image Va(x 1 ) determined in step A. The invention is characterized in that in step A, additionally at least one second measurement is carried out under a second measurement condition b which differs from the first measurement condition a, and depending at least on the measurement data that are obtained in the second measurement, a second spatially resolved, voltage-calibrated image Vb(xi) for the plurality of local points xi is determined from the measurement data obtained in step A. In step A, in both measurements, the luminescence radiation is substantially generated by applying an excitation radiation in a planar manner to the semiconductor structure. The measurement conditions (a, b) of the first and second measurements differ with respect to the intensities and/or spectral compositions of the excitation radiation and/or a predetermined external voltage V ext , which is applied to the semiconductor structure by way of electrical contacting. In addition to each measurement condition (a, b), a voltage-independent, site-independent short-circuit current density (jP,a, jP,b) of the current flowing under the respective measurement conditions in the presence of short-circuit conditions is predetermined and/or measured. In step B, the determination of the spatially resolved, electrical properties at each local point xi is carried out depending on at least the short-circuit current densities (jP,a, jP,b) and a voltage-dependent, site-dependent dark current density (jD,a(xi), jD,b(xi)) for each measurement condition, wherein the dark current densities (jD,a(xi), jD,b(xi)) are at least dependent on the voltage-independent dark saturation current density (j0(xi) and the two voltages (Va(xi), Vb(xi)) resulting from the respective voltage images for site xi.