High-Performance Aligned Carbon Nanotube FETs with Record Transconductance of 3.7 mS/μm

High-performance field-effect transistors (FETs) are fabricated based on high-density aligned carbon nanotube (A-CNT) arrays with low interface state density $(\mathrm{D}_{\text{it}})$ of $5.7\times 10^{11}\text{cm}^{-2}\text{eV}^{-1}$ mainly through improving the quality of gate stack. The champion A-CNT FET with gate length $(\mathrm{L}_{\mathrm{G}})$ of 100 nm exhibits a saturated on-state current $(\mathrm{I}_{\text{on}})$ of 2.45 $\text{mA}/\mu \mathrm{m}$, a peak transconductance $(\mathrm{g}_{\mathrm{m}})$ of 3.7 mS/μm, and a $\mathrm{g}_{\mathrm{m}}/\mathrm{I}_{\text{on}}$ ratio $> 1.5$, which sets a record for ultrathin channel transistors and even exceeds the maximum $\mathrm{g}_{\mathrm{m}}$ of Si planar FETs for the first time. The typical FET with $\mathrm{L}_{\mathrm{G}}$ of 50 nm exhibits an extrinsic cut-off frequency of 302 GHz, far surpassing that of Si MOSFETs with the similar $\mathrm{L}_{\mathrm{G}}$. There is still huge room for improvement in device performance through further optimization of the gate stack in A-CNT FETs.