E-mode RF transistors and circuit model using CVD MoS2

Molybdenum disulfide (MoS ₂ ), a member of the transition metal dichalcogenide (TMD) family, is a 2D semiconductor with a direct bandgap of ~1.8 eV for single layers. Its bandgap allows for high I _on /I _off metal-oxide semiconducting field-effect transistors (FETs). More relevant for radio frequency (RF) wireless applications, theoretical studies predict MoS ₂ to have saturation velocities, V _sat > 3×10 ⁶ cm/s. Recent studies have increased exfoliated MoS ₂ cutoff frequencies by employing a combination of scaling and geometry modification. ¹ However, for industrial scale applications, the mechanical cleavage process is not scalable and, thus far, there have been few studies on chemical vapor deposited (CVD) MoS ₂ RF FETs. ^2,3 Here we take an embedded gate approach ⁴ to yield record transconductance, cutoff frequencies, and current saturation in CVD MoS ₂ . Using measured S-parameters and the MIT-MVS semi-empirical verilog-A model ⁴ we demonstrate analog and mixed-signal circuit operation.