Dresden 2014 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 19: Poster Session 1 (joint session with BP)

CPP 19.43: Poster

Dienstag, 1. April 2014, 09:30–13:00, P1

Control and Analysis of the interface trap density in MIS structures by surface treatments and impedance spectroscopy — •Hippolyte Hirwa, Steve Pittner, and Veit Wagner — Jacobs Universty Bremen, Germany

For high performance electronic devices, reliability and stability are crucial parameters. Reliabilities and stabilities issues in field effect transistors are mainly related to their interface properties. MIS capacitors are very useful tools for investigations of interface traps. Hence, they can be used to evaluate the effect of different surface treatments on the interface traps distribution. In order to improve interface properties in field effect transistors various surface treatments are in use. Octadecyltrichlorsilan (OTS) and Hexamethyldisilazan (HMDS) treatment of SiO2 surfaces are commonly used. Their effects in terms of interface trap density of states and the corresponding time constants are investigated. Impedance measurements have been carried on MIS capacitors fabricated using silicon oxide as insulator with 3 different surface treatments and poly(3-hexylthiophene) as the semiconductor. With a proper equivalent circuit of our MIS structure, the interface trap density was extracted from a fit of the obtained impedance in dependence of frequency and applied DC voltage. A good agreement between the experimental results and the MIS structure model can be obtained upon taking into account the dispersive transport of the bulk and the surface potential fluctuations at the interface. The results reveal that the interface states density and energy distribution can be strongly modified by the surface treatment.