Lateral and vertical scaling of In_0.7Ga_0.3As HEMTs for Post-Si-CMOS logic applications

In this paper, we have experimentally investigated the impact of lateral and vertical scaling of In_0.7Ga_0.3As high-electron-mobility transistors (HEMTs) onto their logic performance. We have found that reducing the In_0.52Al_0.48As insulator thickness results in much better electrostatic integrity and improved short-channel behavior down to a gate length of around 60 nm. Our nearly enhancement-mode 60-nm HEMTs feature V_T = -0.02 V, DIBL = 93 mV/V, S = 88 mV/V, and I_ON/I_OFF = 1.6 × 10⁴, at V_DD = 0.5 V. We also estimate a gate delay of CV/I = 1.6 ps at V_DD = 0.5 V. We have benchmarked these devices against state-of-the-art Si CMOS. For the same leakage current, which includes the gate leakage current, the InGaAs HEMTs exhibit 1.2× more current drive (I_ON) than the state-of-the-art 65-nm low-power CMOS technology at V_DD = 0.5 V.