Germanium MOS capacitors grown on Silicon using low temperature RF-PECVD

Ghada Dushaq, Mahmoud Rasras, Ammar Nayfeh

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


In this paper, Ge metal-oxide-semiconductor capacitors (MOSCAPs) are fabricated on Si using a low temperature two-step deposition technique by radio frequency plasma enhanced chemical vapor deposition. The MOSCAP gate stack consists of atomic layer deposition of Al2O3 as the gate oxide and a Ti/Al metal gate electrode. The electrical characteristics of 9 nm Al2O3/i-Ge/Si MOSCAPs exhibit an n-type (p-channel) behavior and normal high frequency C-V responses. In addition to CV measurements, the gate leakage versus the applied voltage is measured and discussed. Moreover, the electrical behavior is discussed in terms of the material and interface quality. The Ge/high-k interface trap density versus the surface potential is extracted using the most commonly used methods in detemining the interface traps based on the capacitance-voltage (C-V) curves. The discussion included the Dit calculation from the conductance method, the high-low frequency (Castagné-Vapaille) method, and the Terman (high-frequency) method. Furthermore, the origins of the discrepancies in the interface trap densities determined from the different methods are discussed. The study of the post annealed Ge layers at different temperatures in H2 and N2 gas ambient revealed an improved electrical and transport properties of the films treated at T < 600 °C. Also, samples annealed at
Original languageEnglish (US)
Pages (from-to)405107
Issue number40
StatePublished - Sep 12 2017
Externally publishedYes

Bibliographical note

KAUST Repository Item: Exported on 2022-06-03
Acknowledgements: We gratefully acknowledge financial support for this work provided by Masdar Institute of Science and Technology. Also our greatest gratitude to Professor Xiaohang Li and his PhD students Nasir Alfaraj and Wenzhe Guo from the Electrical Engineering Department at King Abdullah University of Science and Technology (KAUST) for helping us with the Rutherford back scattering measurements.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.


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