First Demonstration of 40-nm Channel Length Top-Gate WS2 pFET Using Channel Area-Selective CVD Growth Directly on SiOx/Si Substrate
Area-selective channel material growth for 2D transistors is more desirable for volume manufacturing than exfoliation or wet/dry transfer after large area growth. We demonstrate the first top-gate WS 2 p-channel field-effect transistors (p-FETs) fabricated on SiOx/Si substrate using channel area-selective CVD growth. Smooth and uniform WS 2 comprising approximately 6 layers was formed by area-selective CVD growth in which a patterned tungsten-source/drain served as the seed for WS 2 growth. For a 40 nm gate length transistor, the device has impressive electrical characteristics: on/off ratio of ~106, a S.S. of ~97 mV/dec., and nearly zero DIBL.
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Low Dimensional Material & Device
Transistor research team at TSMC is also exploring devices built on materials having intrinsically 2D or 1D carrier transport (low-dimensional transport). Transition metal dichalcogenides, graphene nanoribbons, and carbon nanotubes, among others, are being investigated theoretically and experimentally. TSMC research work is both internally conducted and/or in collaboration with our academic partners through joint development projects, or by active technical participation in leading research consortia or research institutes worldwide. Here we invite you to explore some of TSMC’s recent published work in these fields of active exploratory research.
The benefits of using 2D and 1D materials include high mobility at atomic thickness, excellent gate control, and potential applications for low-power and high-performance devices. Thus, transistor scaling may be extended. In a recent publication, we have successfully demonstrated the growth of wafer-scale h-Boron Nitride monolayer, which is able to efficiently protect the channel 2D semiconductors from process damages and the charge impurity scattering from adjacent dielectrics. 1D semiconducting carbon nanotubes, with processes compatible with the backend-of-line (BOEL) fabrication temperature (< 400 oC), are a potential component for achieving monolithic 3D ICs. The proof-of-concept monolithic integration of carbon nanotube transistors on our 28 nm CMOS technology wafers has also been demonstrated.