Sub-5 nm monolayer KMgX (X = P, As, Sb)-based homogeneous CMOS devices for high-performance applications

For CMOS electronics, the channel materials - which can offer symmetrical performance for n- and p-type devices, along with the ability to scale transistors down to the ultra-scale limit - are crucial in the next era beyond silicon. Monolayer KMgX (X = P, As, Sb) not only possesses an atomically thin structure, but also exhibits high mobility for both electrons and holes; being advantageous for symmetrical performance and shrinking a device's size. Based on first-principles calculations, the device performance limit of sub-5 nm monolayer KMgX (X = P, As, Sb) metal-oxide semiconductor field-effect transistors (MOSFETs) with a double-gated setup are investigated. The results show that, for all three KMgX configurations (X = P, As, Sb), both n- and p-type MOSFETs can meet the ITRS 2013 requirements for 2028 horizon in high-performance applications, even as L_g reduces to 3 nm. The ON-state currents of those systems exceed the performance of most previously reported monolayer MOSFETs. In particular, the 5 nm-L_g n-type KMgSb and KMgAs MOSFETs exhibit ultra-high ON-state currents of 3463 and 3248 μA μm^-1, respectively. Furthermore, the ratios of subthreshold swing, ON-state current, fringe capacitance, delay time, and power-delay product between n- and p-type devices, demonstrate a high degree of symmetry. Our results suggest that the use of monolayer KMgX (X = P, As, Sb) MOSFETs would be highly advantageous for the development of sub-5 nm homogeneous CMOS electronics.