Method and apparatus for detecting mechanical defects in a semiconductor device, particularly in a solar cell arrangement

A method for detecting mechanical defects in a semiconductor device, having at least one pn-junction in a semiconductor layer formed of a semiconductor material that is characterized by an indirect band junction;

• said method comprising:
• applying to the at least one pn junction, a voltage for operating the pn junction in a transmitting direction;
• optically detecting and analyzing radiation behavior of the semiconductor layer generated by the applied voltage, at least for partial ranges of the semiconductor layer;
• and
• performing at least one of the following,
• i) automatically examining the radiation behavior of the semiconductor layer for abrupt substantially one-dimensional changes of intensity along the semiconductor layer, and identifying detected intensity changes as mechanical defects of the semiconductor device;
• and
• ii) automatically integrating radiation intensity of at least a first partial range of a first semiconductor layer, automatically comparing a resulting integral with an integral of radiation intensity of at least one comparison range of the same semiconductor layer or of a second semiconductor layer, and identifying the first partial range as either defective or free of defects, based on a result of an automatic comparison of the two integrals.

Apparatus for detection of mechanical defects of a semiconductor device having at least one pn junction formed in a semiconductor material that is characterized by an indirect band junction;

• said apparatus comprising:
• at least one electrode which is connected with a p-conducting range of the semiconductor device;
• at least one electrode, which is connected with the n-conducting range of the semiconductor device;
• voltage supply connections which are connected with said electrodes for supplying a voltage sufficient to operate the pn junction in a transmitting direction;
• a device for optical detection and analysis of radiation behavior of the semiconductor layer generated by the supplied voltage, at least for partial ranges of the semiconductor layer, said optical detection device comprising a filter unit which is constructed such that at least one of i) an electromagnetic radiation in the spectral region with a lower wavelength than infrared is blocked;
• and ii) the radiation of one or more pn junctions is isolated;
• an image data storage area for storing a radiation image of a semiconductor layer;
• a first program storage area containing an image processing program configured for automatic examination of a radiation image with respect to abrupt, substantially one-dimensional intensity changes and for identification of detected intensity changes as mechanical defects of the semiconductor device;
• and
• a second program storage area containing a program for analysis of the radiation image with respect to electric effects of identified mechanical defects.