Defects in NTD silicon for power electronics

The project aims at clarifying what causes increased leakage currents sometimes observed in semi-conductor high power diodes made from neutron transmutation doped (NTD) float-zone (FZ) single-crystal silicon. Power electronic components are vital in the control and conversion of electric power particularly in connection with renewable energy sources. Increased leakage currents will increase the losses and thus reduce the efficiency. At present, it is not possible to detect whether a given poly-crystal (the source material), a given FZ-crystal or even the finished NTD silicon crystal is going to yield increased leakage current in the finished diodes. There is, however, strong indication that poly-crystalline material produced from trichlorosilane is substantially better in this respect. It is the clear goal of this project to understand the origin of the difference in material properties as well as finding a method to predict whether the material will be problematic as early in the lifecycle as possible.

Funded by: Grant DFF – 1337-00139 from the Danish Council for Independent Research | Technology and Production Sciences.

Industrial partners: Topsil Semiconductor Materials A/S (

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