Exploring materials and strategies for metal contacts of advanced 2D devices

The Silicon semiconductor technology has been the main driver in the last 60 years in the advancement of our daily life. The development of electronics devices, sensors, automation, computers, cameras and smartphones based on this material will reach in the near future ultimate limits due to the continuous downscaling of the physical size of devices and wires to the nanometer scale. The miniaturization of circuits seems to have reached a possible halt, since transistors can only be shrunk down to a certain size and not further beyond. Thus, there is a pressing need to complement Si CMOS technology with new materials to fulfil the future computing requirements as well as the needs for diversification of applications.

In this framework, two-dimensional (2D) materials offer prospects of unprecedented advances in device performance at the sub-nanometer scale. Their amazing potential has proven to be a possible solution to overcome the limitations of silicon technology, where the combination of 2D materials with silicon chips promises to surpass the current technological limitations. With that vision, imec investigates their integration, in particular for beyond silicon CMOS and advanced memory technologies. However, many challenges still remain to unlock their incorporation into the Si-technology, especially the contact module at the source/drain area in a Field-Effect Transistor device. The quest towards lowering the contact resistance is today the main focus to boost current device performances.

In this project, the PhD candidate will explore different routes to improve the metal contact with the 2D channel. The epitaxy and/or deposition of specific metals, semimetals, 2D metals will be at the core of this project. Various deposition techniques such as Molecular Beam Epitaxy, Physical Vapor Deposition and Atomic Layer Deposition will be used to research the ideal combination between the metal and the 2D channel. The PhD candidate will be responsible for the deposition/epitaxy, will make use of different complementary characterization techniques to provide an in-depth and thorough understanding on the impact of the metal to the 2D channel and finally will explore different integration schemes such as top contacts versus side contacts.

At imec, we have a large expert team with various backgrounds in materials and deposition techniques, state of the art 200mm and 300mm process lines, laboratories, device learning and modelling. The PhD candidate will be part of the Advanced Deposition Channel team at imec, with strong links to the Material Engineering department of KU Leuven.