Tunnel Field Effect Transistor based on Few-Layer Black Phosphorus

Speaker: Hussam Qasem
Affiliation: UCLA Ph.D. Candidate

Abstract:  Aggressive scaling of Silicon based MOSFETs in the past decades have contributed immensely to the performance increase of modern electronics. However, at extreme scaling nodes, what was a solution is now the problem when power dissipation in its static and dynamic form have magnified and already reached the cooling limits. The static power dissipation is related to the short channel effect and can be limited by using other material systems that is immune to the short channel effect such as, two-dimensional semiconductors. The dynamic power dissipation can be reduced by allowing the frequency to increase without costing power dissipation. This can be a possible if the device is not designed on a thermionic injection which is limited by the subthreshold swing of 60 mV/dec, but rather on a tunneling transport mechanism which in theory can go far beyond the 60 mV/dec. It is, however, the low saturation ON current of the Si based T-FETs that hinder their progress.

In our work, we combine the high mobility two-dimensional semi-conductive black phosphorus material, which has a: 1) low effective mass value, 2) favorable band gap value, and 3) short electrostatic length and therefore immune to the short channel effect and, with the vital device design of Tunnel-FETs.  A combination of scrupulous black phosphorus FET device optimization process, e-beam lithography microalignment skill, and shadow deposition technique was used to realize our black phosphorus-based T-FET device. We have achieved high ON current values (1.4 uA/um), high ON/OFF ratio (10⁵), high mobilities (300-400 cm²V-¹S-¹), and low subthreshold swing (70 mV/dec). We have also marked these T-FET metrics against different temperatures, and also against the crystal orientation of the two-dimensional material. This research proof the applicability of Van der Wal materials in tunnel FET devices in particular, and low power electronics in general, and widen the path for greener, high-performance, and energy-efficient devices.

Biography:  Hussam received his B.Sc degree in electrical engineering from King Abdul-Aziz University.  He then joined KACST as a research assistant.  In 2012, Hussam joined DRL lab and received his M. Sc. in Electrical Engineering from UCLA in 2014.  His research interest is in low-power, energy-efficient nanoelectronics.

For more information, contact Prof. Kang L. Wang (wang@ee.ucla.edu)

Date/Time:
Date(s) - Jun 04, 2019
10:00 am - 12:00 pm

Location:
E-IV Faraday Room #67-124
420 Westwood Plaza - 6th Flr., Los Angeles CA 90095