Detection of BO2 in silicon

Boron-oxygen complexes are one of the main reasons why solar cells degrade, when irradiated with sun light. Hence it is important to measure the boron-oxygen density in silicon fast, destruction free and with a high resolution.

The boron-oxygen complexes can be activated by irradiating the sample with light and deactivated by heating the sample at 200 °C for several minutes. This can be used similar to the iron determination, to determine the relative boron-oxygen density by lifetime measurements before and after the activation and deactivation of the defect complex.

The boron-oxygen density is determined via:

For the boron-oxygen determination a calibration factor CBO is used, which depends on the injection and doping concentration. With the MDPmap and the heated sample stage a determination of the boron-oxygen concentration is possible for mc- and mono-Si with a high resolution.