DIRECT BONDING OF GAAS FILMS ON SILICON CIRCUITS BY EPITAXIAL LIFTOFF

Epitaxial liftoff has emerged as a viable technique to integrate GaAs with silicon. The technique relies on the separation of a thin epi-GaAs film from its substrate followed by direct bonding of the thin film to a silicon substrate. The silicon substrate has to meet certain planarity and smoothness conditions in order to obtain high quality bonding. Unfortunately, processed silicon IC chips do not satisfy these conditions. In this paper, we report on the results of two different planarization techniques, plasma etch back and chemical-mechanical polishing, to integrate GaAs LEDs with silicon circuits using epitaxial liftoff. 4 by 8 arrays of GaAs LEDs have been integrated with silicon driver circuits using plasma etch back. We also have lifted off areas as large as 500 mm2 and bonded them on 5'' device wafers by chemical-mechanical polishing. This can be essential for mass production of optoelectronic devices based on epitaxial liftoff.