@article{13543, author = {Brendan McBennett and Yuka Esashi and Nicholas Jenkins and Albert Beardo and Yunzhe Shao and Emma Nelson and Theodore Culman and Begoña Abad and Michael Tanksalvala and Travis Frazer and Samuel Marks and Weilun Chao and Sadegh Yazdi and Joshua Knobloch and Henry Kapteyn and Margaret Murnane}, title = {Low-density diamondlike amorphous carbon at nanostructured metal-diamond interfaces}, abstract = {

Next-generation nanoelectronic, energy, and quantum technologies require increasingly stringent thermal, optical, mechanical, and electrical properties of component materials, often surpassing the limits of widely used materials such as silicon. Diamond, an ultrawide bandgap semiconductor, is a promising material for these applications because of its very high stiffness, thermal conductivity, and electron mobility. However, incorporating diamond into devices that require high-quality metal-diamond interfaces is challenging. In this work, we use a suite of electron microscopy measurements to reveal an ultrathin amorphous carbon layer that emerges at metal-diamond interfaces after electron beam lithography. Using extreme ultraviolet scatterometry, we nondestructively determine lower bounds on the layer's Young's modulus and thermal conductivity, which at  and  W/() are indicative of a diamondlike form of amorphous carbon with high  bonding. However, extreme ultraviolet coherent diffractive imaging reflectometry and energy-dispersive x-ray spectroscopy measurements indicate a low and likely inhomogeneous density in the range of . The low density of such a stiff and conductive layer could indicate that it contains nanometer-scale voids or atomic-scale vacancies. The appearance of this unusual layer illustrates the nanofabrication challenges for diamond and highlights the need for better techniques to characterize surfaces and interfaces in nanoscale devices.

}, year = {2024}, journal = {Phys. Rev. Mater.}, volume = {8}, pages = {096001}, month = {2024-09}, publisher = {American Physical Society}, url = {https://link.aps.org/doi/10.1103/PhysRevMaterials.8.096001}, doi = {10.1103/PhysRevMaterials.8.096001}, }