Hole mobility and remote scattering in strained InGaSb quantum well MOSFET channels with Al2O3 oxide

Hall mobility and major scattering mechanisms in surface and buried MBE grown strained InGaSb quantum well (QW) MOSFET channels with in‐situ grown Al₂O₃ gate oxide are analyzed as a function of sheet hole density, top‐barrier thickness and temperature. Mobility dependence on Al_0.8Ga_0.2Sb top‐barrier thickness shows that the relative contribution of interface‐related scattering is as low as ～30% in the surface QW channel. An InAs top capping layer reduces the interface scattering even further; the sample with 3 nm total top‐barrier thickness demonstrates mobility of 980 cm²/Vs giving sheet resistance of 4.3 kΩ/sq, very close to the minimum QW resistance in the bulk. The mobility–temperature dependences indicate that the interface‐related scattering is dominated by remote Coulomb scattering at hole densities <1 × 10¹² cm^–2. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)