Complementary Vertical FETs (CVFETs) Enabled by a Novel Dual-Side Process

Abstract

We demonstrated the monolithically integrated complementary vertical-channel field-effect-transistor (CVFET) inverters with an innovative dual-side process (DSP). Good electrical characteristics for both NMOS and PMOS were achieved: transconductance of $69~\mu $ S/ $\mu $ m, ${\mathrm{I}}_{\text {on}} = 18~\mu $ A/ $\mu $ m (@ VGS – ${\mathrm{V}}_{\text {T}} =0.45$ V, ${\mathrm{V}}_{\text {DD}}=0.65$ V), Ion/ ${\mathrm{I}}_{\text {off}} = 3.1\times 10^{{6}}$ , SS =69 mV/dec and DIBL =12 mV/V for the top NMOS, and transconductance of $592~\mu $ S/ $\mu $ m, ${\mathrm{I}}_{\text {on}} = 136~\mu $ A/ $\mu $ m (@ VGS – ${\mathrm{V}}_{\text {T}} = -0.45$ V, ${\mathrm{V}}_{\text {DD}}= -0.65$ V), Ion/ ${\mathrm{I}}_{\text {off}} = 5.4\times 10^{{6}}$ , SS =72 mV/dec and DIBL=18 mV/V for the bottom PMOS. The functional CVFET inverters show well-balanced voltage transfer characteristics (VTC) up to 1.2 V with a maximum gain of 13 V/V. Furthermore, the CVFETs also featured with crystal-Si vertical channels and common self-aligned high- $\kappa $ metal gates. The CVFET structure and its integration scheme are strong candidates for the applications of advanced logic technologies.