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InGaAs Inversion Layer Mobility and Interface Trap Density from Gated Hall Measurements



Thenappan Chidambaram, Dmitry Veksler, S Madisetti, Michael Yakimov, Vadim Tokranov, Serge Oktyabrskiy


In this work, we use gated Hall method for direct measurement of free carrier density and electron mobility in inversion InGaAs MOSFET channels. At room temperature, the highest Hall mobility of 1800 cm2/Vs is observed at electron density in the channel 1x1012 cm-2. A comparison with mobility values estimated from transistor characteristics reveals a significant underestimation of mobility which arises from overestimation of channel density obtained from C-V measurements. Temperature dependence of the electron mobility provides the evidence that remote Coulomb scattering dominates at electron density < 3x1011 cm-2. Contrary to the capacitance-based methods commonly used for extraction of interface trap density, gated Hall method can separate the contributions of fast-trapped charges and free carriers in the channel to the total charge of a MOS capacitor. This allows for reliable estimation of trap density at the III-V/high-k interface including boarder traps. The results illustrate that even high- quality interfaces providing high-mobility transport suffer from fast border traps above the conduction band. In contrast with Si where the effect of boarder traps is small, in low density-of-state InGaAs channel material they account for as much as half of the electrons being trapped and wasted for transport increasing switching energy and dissipated power.
IEEE Electron Device Letters


Chidambaram, T. , Veksler, D. , Madisetti, S. , Yakimov, M. , Tokranov, V. and Oktyabrskiy, S. (2016), InGaAs Inversion Layer Mobility and Interface Trap Density from Gated Hall Measurements, IEEE Electron Device Letters, [online], (Accessed May 26, 2024)


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Created December 11, 2016, Updated October 12, 2021