Advancing Monolayer 2-D nMOS and pMOS Transistor Integration From Growth to Van Der Waals Interface Engineering for Ultimate CMOS Scaling

Autor: Carl H. Naylor, Chelsey Dorow, O'brien Kevin P, Kirby Maxey, Arnab Sen Gupta, Andy Hsiao, Tronic Tristan A, Penumatcha Ashish Verma, Scott B. Clendenning, Gosavi Tanay, Matthew V. Metz, Michael Christenson, Sudarat Lee, Robert L. Bristol, Uygar E. Avci, Alaan Urusa, A. A. Oni, Hui Zhu
Rok vydání: 2021
Předmět:
Zdroj: IEEE Transactions on Electron Devices. 68:6592-6598
ISSN: 1557-9646
0018-9383
Popis: 2-D-material channels enable ultimate scaling of MOSFET transistors and will help Moore's Law scaling for years. We demonstrate the state of both n- and p-MOSFETs using monolayer transition metal dichalcogenide (TMD) channels of sub-1 nm thickness and manufacturable CVD, molecular beam epitaxy (MBE), or seeded growth. nMOS devices on transferred MBE MoS₂ using novel contact metal show low variation, one of the lowest reported contact resistances ( $R_{c}$ ) of 0.4 kΩ ·μ m, low hysteresis, and good subthreshold swing (SS) of 77 mV/dec. pMOS devices using CVD WSe₂ show 89 mV/dec SS, best reported for pMOS on grown films, but on-current remains behind nMOS. We show $R_{C}$ is improved by 5x by using a bake process prior to contact metal deposition. Transfer-free, area-selective seeded growth techniques for WS₂ and MoS₂ are demonstrated as options for wafer-scale TMD channel growth. WS₂ transistors achieve 10 μA/μm on-current, highest reported on WS₂ using seeded growth. A new capacitance method is shown to monitor 2-D material contact interface quality. Gate-oxide interface engineering through metal seeding and atomic layer deposition (ALD) demonstrates that a single 2-D channel material can selectively make pMOS or nMOS transistors, alike Si CMOS, and can also be used as a method to achieve p-type doping. We compare back-gated bare channel devices with dual-gate devices and observe hysteresis-free operation and an improvement in mobility with proper passivation.
Databáze: OpenAIRE