Complementary carbon nanotube metal-oxide-semiconductor field-effect transistors with localized solid-state extension doping

Low-dimensional semiconductors such as one-dimensional carbon nanotubes could be used to shrink the gate length of metal-oxide-semiconductor field-effect transistors (MOSFETs) below the limits of silicon-based transistors. However, the development of industry-compatible doping strategies and polarity-control methods for such systems is challenging. Here we report top-gate complementary carbon nanotube MOSFETs in which localized conformal solid-state extension doping is used to set the device polarity and achieve performance matching. The channel of the transistors remains undoped, providing complementary metal-oxide-semiconductor-compatible n- and p-MOSFET threshold voltages of +0.29 V and -0.25 V, respectively. The foundry-compatible fabrication process implements localized charge transfer in the extensions from either defect levels in silicon nitride (SiNx) for n-type devices or an electrostatic dipole at the SiNx/aluminium oxide (Al2O3) interface for p-type devices. We observe SiNx donor defect densities approaching 5 x 10(19) cm(-3), which could sustain carbon nanotube carrier densities of 0.4 nm(-1) in the extensions of scaled nanotube devices. Our technique is potentially applicable to other advanced field-effect transistor channel materials, including two-dimensional semiconductors.

Automated summary

This article investigates a top-gate complementary carbon nanotube MOSFET, in which localized solid-state doping is used to set the device polarity and achieve performance matching. The technique is potentially applicable to other advanced field-effect transistor channel materials.