Strain determination in the Si channel above a single SiGe island inside a field effect transistor using nanobeam x-ray diffraction

N. Hrauda, J. J. Zhang, E. Wintersberger, T. Etzelstorfer, J. Stangl, D. Carbone, C. Biasotto, V. Jovanovic, L. K. Nanver, J. Moers, D. Grützmacher, G. Bauer

Published 2010-11-17Version 1

SiGe islands are used to induce tensile strain in the Si channel of Field Effect Transistors to achieve larger transconductance and higher current driveabilities. We report on x-ray diffraction experiments on a single fully-processed and functional device with a TiN+Al gate stack and source, gate, and drain contacts in place. The strain fields in the Si channel were explored using an x-ray beam focused to 400 nm diameter combined with finite element simulations. A maximum in-plane tensile strain of about 1% in the Si channel was found, which is by a factor of three to four higher than achievable for dislocation-free tensile strained Si in state-of-the-art devices.