Scattering mechanisms in In0.7Ga0.3As/In0.52Al0.48As quantum-well metal-oxide-semiconductor field-effect transistors

In this paper, we modeled the scattering-limited effective mobility (μeff) of an In0.7Ga0.3As quantum-well (QW) metal-oxidesemiconductor field-effect-transistor (MOSFET). We fabricated In0.7Ga0.3As/In0.52Al0.48As QW MOSFETs with Al2O3 = 2 nm by ALD, and the devices exhibited a μeff value close to 7000 cm2/V s at 300 K and good electrostatic integrity. Detailed analysis on μeff of the In0.7Ga0.3As/In0.52Al0.48As QW MOSFETs was performed to investigate various sources of the scattering mechanism, such as surface-roughness scattering (SRS), phonon scattering (PHS) and Coulombic scattering (CS). In doing so, we attempted to separately model the three different scattering mechanisms from their dependency upon the vertical electric field intensity (Eeff). We demonstrated that μeff of the InGaAs QW MOSFET was governed by a combination of three scattering components according to Mathiessen’s rule, yielding excellent agreement with experimental data.