TY - JOUR AU - Brendan McBennett AU - Yuka Esashi AU - Nicholas Jenkins AU - Albert Beardo AU - Yunzhe Shao AU - Emma Nelson AU - Theodore Culman AU - Begoña Abad AU - Michael Tanksalvala AU - Travis Frazer AU - Samuel Marks AU - Weilun Chao AU - Sadegh Yazdi AU - Joshua Knobloch AU - Henry Kapteyn AU - Margaret Murnane AB -

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.

BT - Phys. Rev. Mater. DA - 2024-09 DO - 10.1103/PhysRevMaterials.8.096001 N2 -

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.

PB - American Physical Society PY - 2024 EP - 096001 T2 - Phys. Rev. Mater. TI - Low-density diamondlike amorphous carbon at nanostructured metal-diamond interfaces UR - https://link.aps.org/doi/10.1103/PhysRevMaterials.8.096001 VL - 8 ER -