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Source/drain electrodes contact effect on the stability of bottom-contact pentacene field-effect transistors AIP Advances 2, 022113 (2012) All-metallic lateral spin valves using Co2Fe(Ge0.5Ga0.5) Heusler alloy with a large spin signal Appl. Phys. Lett. 100, 052405 (2012) Contact transport of focused ion beam-deposited Pt to Si nanowires: From measurement to understanding Appl. Phys. Lett. 100, 053503 (2012) Ab initio quantum transport simulation of silicide-silicon contacts J. Appl. Phys. 111, 014305 (2012) Impact of fluorine treatment on Fermi level depinning for metal/germanium Schottky junctions Appl. Phys. Lett. 99, 253504 (2011) Additional information on J. Appl. Phys. A new mechanism of contact resistance formation in ohmic contacts with high dislocation density is proposed. Its specific feature is the appearance of a characteristic region where the contact resistance increases with temperature. According to the mechanism revealed, the current flowing through the metal shunts associated with dislocations is determined by electron diffusion. It is shown that current flows through the semiconductor near-surface regions where electrons accumulate. A feature of the mechanism is the realization of ohmic contact irrespective of the relation between the contact and bulk resistances. The theory is proved for contacts formed to III-V semiconductor materials as well as silicon-based materials. A reasonable agreement between theory and experimental results is obtained.

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PACS 72. 70.+m, 73.40.Kp, 73.50.Td γ-ray radiation effect has been studied on transport and noise properties of high electron mobility transistors (HEMTs) with gate lengths in the range from 350 to 150 nm at room temperature. Current-voltage (I -V) characteristics of the devices demonstrate higher radiation hardness to 60 Co γ-rays up to doses of 10 9 Rad at larger gate lengths. This confirms the very important role of surface passivation for channel transport of the HEMTs. The deviation of the I -V characteristics parameters saturated current, transconductance, channel conductance, and threshold voltage does not exceed 20% at highest radiation dose. The noise spectra of pre-irradiated devices and after γ-irradiation show different frequency dependences corresponding to different fluctuation processes in the HEMTs. The results are confirmed by dynamic current measurements of the channel conductivity.