Fundamental Devices in 2-D TMD Semiconductors

Suny Polytechnic Institute, Albany NY

Investigators

Abstract

Transistor scaling, best embodied in Moore's law, has enabled the unprecedented advancement in computing technologies over the past quarter century. Scaling, however, is expected to slow down significantly due to fundamental limitations. In response, new materials are sought that can continue the historical rate of scaling. Transition metal dichalcogenide semiconductors are promising new channel materials because they are naturally thin. Thinning of the channel is one of the most important recent developments in the manufacturing of advanced semiconductor devices that help to achieve better electrostatic control. To that end, the dichalcogenide systems are expected to provide the thinnest semiconducting channel material, surpassing the limit that can be achieved in bulk semiconductors. In the proposed research, students and researchers will fabricate devices in the dichalcogenide systems. The principal investigator will train both graduate, undergraduate, and high school students, particularly those underrepresented in science, to fabricate and characterize semiconductor devices. These devices will be used as hands-on learning tools in the courses offered at the university. Also, the principal investigator will work with at-risk urban youth from Albany, Troy, Schenectady, and Newburgh to educate them on the growing opportunities in the regional semiconductor industry. The principal investigator will also work with staff to host two one-day summer workshops for secondary school teachers on classroom integration of nanoelectronics modules developed under the proposed middle school/high school outreach efforts. New materials and device concepts are needed to continue the historical increase in functionality of computing devices. In the proposed research, a reconfigurable device will be developed that can morph into the three most fundamental devices. These devices are p-n diode, metal-oxide-semiconductor field-effect transistor, and bipolar junction transistor. Using these devices, the principal investigator will demonstrate basic logic functions with fewer transistors. These research thrusts are possible in the recently discovered transition metal dichalcogenide semiconductors because they are naturally thin, which is particularly suited for implementing the gating technique pioneered by the group. Because a single device can accomplish all three device functions, the proposed research can uniquely provide fundamental linkages between material properties and device performance that would be difficult to attain had the devices were fabricated individually. This research will use the state-of-the-art 300mm fabrication facility located at the university to fabricate highly scaled devices. It will train students on the challenges of device integration and to the opportunities such an advanced fabrication facility provides. At the fundamental level, this research will provide a unique insight into how the three devices are intimately linked. These devices can achieve rectification, switching, and current amplification, respectively. This research will measure the key figure-of-merit of each device and provide linkages to material properties, including the interface trap states. With reduced dimensions, many-body effects become important. Although many-body effects are not needed to understand the properties of modern transistors, their role will become significant as transistors continue to shrink. The proposed research will help to inform the semiconductor manufacturers to the importance of many-body effects by measuring the excitonic properties and the band gap, which can renormalize when the semiconductor is doped. The results of this research will be disseminated to the growing number of semiconductor companies that are co-located at the university.