Performance and carrier transport analysis of In0.7Ga0.3As quantum-well MOSFETs with Al2O3/HfO2 gate stack

• We fabricated In0.7Ga0.3As QW MOSFETs with Al2O3/HfO2 gate stack.
• Fabricated devices shows excellent transconductance characteristics at Lg > 1 μm region.
• We carried out analytical modeling on intrinsic and extrinsic transconductance.

In this paper, we have fabricated and characterized In0.7Ga0.3As 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 Lg = 4 μm exhibits a record maximum transconductance (gm_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, VT = −0.25 V to −0.2 V and DIBL = 40–50 mV/V, as Lg decreases from 10 μm to 4 μm. Furthermore, we have explored the impact of source resistance (RS) onto the device characteristics of the InGaAs QW MOSFETs. In doing so, we have modeled both measured extrinsic transconductance (gm_ext) and intrinsic transconductance (gm_int) as a function of Lg.