The authors thank Cyril Cabral, Roy Carruthers, Robert Purtell, Patricia O Neil, Cedrik Coia, Martin Tremblay, Simon Gaudet, Patrick Desjardins and Jean Jordan-Sweet for contributions to the experiments and stimulating discussions. We are very grateful to Fran ois d Heurle and Jim Harper for sound scientific guidance and unfailing support. Thanks to Fran ois d Heurle again and to Prof. Katy Barmak for thorough reviews of this manuscript that led to major modifications and surely deeper understanding. Special acknowledgments are given to Jorge Kittl of Texas Instruments for stimulating discussions and for the access to his electrical results for the device characterisation section. The synchrotron XRD experiments were conducted under DOE contract DE-AC02-76CH-00016. C. Detavernier acknowledges the Fonds Voor Wetenschappelijk Onderzoek-Vlaanderen (FWO) for financial support.

The authors would also like to thank the following collaborators from AMD for valuable technical discussions and data input: Simon Chan, Witek Maszara, Thorsten Kammler and David Brown. We also acknowledge the following collaborators for providing analytical results and interpretation: Paul King (AES), Holger Saage (TEM), Hans-Juergen Engelmann (TEM), Liliana Thompson (TEM), Heiko Stegmann (TEM and micro-diffraction) and Max Sidorov (TEM).