Performance and carrier transport analysis of In_0.7Ga_0.3As quantum-well MOSFETs with Al₂O₃/HfO₂ gate stack

In this paper, we have fabricated and characterized In_0.7Ga_0.3As quantum-well (QW) metal-oxide-semiconductor field-effect-transistors (MOSFETs). We have employed the gate dielectric of the Al₂O₃/HfO₂ (0.6/2 nm) bi-layer stack by ALD. The fabricated device with L_g = 4 μm exhibits a record maximum transconductance (g_m-max) in excess of 520 μS/μm at >1 μm region, and reasonably good electrostatic integrity, such as SS = 110 mV/decade and DIBL = 43 mV/V. Also, we have investigated the gate length scaling behavior in terms of output, transconductance, and transfer characteristics. In particular, our devices feature very uniform values of the electrostatic integrity, such as SS = 100-110 mV/decade, V_T = -0.25 V to -0.2 V and DIBL = 40-50 mV/V, as L_g decreases from 10 μm to 4 μm. Furthermore, we have explored the impact of source resistance (R_S) onto the device characteristics of the InGaAs QW MOSFETs. In doing so, we have modeled both measured extrinsic transconductance (g_m-ext) and intrinsic transconductance (g_m-int) as a function of L_g.