N-Type Dual Vertical C-Shaped-Channel Nanosheet FETs with Ultra-Thin Channels for High Performance Logic Application

We demonstrate a novel n-type dual vertical C-shaped-channel nanosheet field-effect-transistor (dVCNFET) with ultra-thin channels, featured by self-aligned and replaced high-κ metal gates aiming at high-performance logic circuits. The dVCNFETs were fabricated by high-quality Si/SiGe/Si epitaxy, Si epi growth on SiGe and SiGe bidirectional cross etching method, enabling precise control over channel thickness (Tchannel), gate length and self-aligned gate formation. The space between channels were controlled by etch but not lithography, which means that the space can also be well controlled at advanced technology. This fabrication method is complementary metal oxide semiconductor technology compatible and nanosheets with Tchannel < 3 nm were obtained. Moreover, the device exhibits excellent performance and gate control, with Ion = 204 μA/μm (@ VGS – VT = 1 V, VDS = 0.65 V), Ion/Ioff = 8.69 × 10⁸, SS = 61 mV/dec and DIBL = 17 mV/V.