2008 NSTI Nanotechnology Conference and Trade Show - Nanotech 2008 - 11th Annual

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Clean Technology 2008

Contribution of NIEL for gain degradation (_) of silicon transistor: 110MeV Si8+ ion irradiated at 77K and at 300K

C.M. Dinesh, R. Ramani, M.C. Radhakrishna, S.A. Khan, D. Kanjilal
Bangalore University, IN

transistor, irradiation, defects, junction

The concept of non-ionizing energy loss (NIEL) has been found useful for characterizing displacement damage defects in materials and devices. When bipolar junction transistors are exposed for high energy irradiation cause functional failure due to surface and bulk defects. In the present work we report the effect of 110 MeV Si8+ ion irradiation in the fluence range 5 x 109to 1 x 1013 ions cm-2 on NPN power transistors (2N6688 manufactured by BEL, India) at room temperature (300K) and at liquid nitrogen temperature (77K). The variations in electrical parameters are correlated with non- ionizing energy deposition due to MeV ion irradiation using TRIM Monte Carlo code. Systematic electron transport measurements for unirradiated and irradiated devices showed the base current increases and collector current decreases with increase in ion fluence. The output collector characteristics are studied as a function of total ionizing dose (TID) and total displacement damage dose (Dd). It is observed that the shift in the output saturation voltage is considerably less for heavy ion irradiation compared to lighter ions like lithium ion irradiation [1]. The gain of the transistor degrades with ion irradiation. Reverse biased base leakage current increases with increase in ion fluence. The observed results are almost independent of the irradiation temperature. These studies help to improve the device fabrication technology to make Radiation Hard Devices for advanced applications. Reference:[1] C.M. Dinesh, Ramani et., al., International conference on Ion Beam Analysis, Hydrabad 2007.

Nanotech 2008 Conference Program Abstract