In the last few decades, the device community has explored a large number of technologies beyond silicon, that not only allow for further shrinkage in electronic systems size and power but can also provide new features, such as mechanical flexibility, large area coverage at low cost and simplified 3D integration. Two-dimensional electronics based on single-layer MoS2 synthesized by chemical vapor deposition offers significant advantages for realizing large-scale flexible systems owing to the ultrathin nature, excellent transport properties and stable crystalline structure of MoS2.
Despite all the progress, the MoS2 electronics demonstrated so far is limited to single or few-device-scale circuits build on exfoliated flakes due to the many challenges associated with the uniformity and yield control in both material growth and device fabrication. This thesis addresses issues which are crucial for realizing reliable, high yield complex circuits using emerging 2D material, MoS2 : (1) Develop large area material synthesis and transfer methods , as well as some of the first technologies for reliable enhancement mode MoS2 transistors. (2) Design a scalable PDK for MoS2 and implemented both digital circuits (combinational and sequential logics) and analog circuits (power management circuits).(3) Study the impact of devices variability to circuit yield and improve the yield to 100% with circuits of 10k transistors after material, devices and circuits co-optimization. (4) Demonstrate two practical applications using CVD MoS2: active matrix backplane circuits for transparent display and radio frequency energy harvester. (5) Demonstrate the first air stable CMOS technology monolithically integrated on WSe2 to offer low power electronic solution.
This thesis has, in summary, provided important guidelines on how to take a new proof-of-concept material/device and make it into a useful technology to enable practical applications.
Lili Yu is a Ph.D. candidate in the department of Electrical Engineering and Computer Science at MIT and is working in the Microsystems Technology Laboratory under the supervision of Professor Tomas Palacios. Her graduate work at MIT focus on MoS2 electronics and how to extend the work beyond the single transistor level to system level prototype. She solved issues in devices, circuits design and yield to enable a robust and high performance technologies. Before attending MIT, Lili earned B.S in Physics from Pecking University, China.