Strained InxGa(1-x)As/InP near surface quantum wells and MOSFETs

We present electronic band structure properties of strained InxGa(1-x)As/InP heterostructure near surface quantum wells oriented in the (100) crystallographic direction using eight-band k & BULL; p theory, which are further parameterized by an energy level, effective mass, and nonparabolicity factor. The electronic band structure parameters are studied for the well composition of 0.2 & LE; x & LE; 1 and thickness from 5 to 13 nm. The bandgap and effective mass of the strained wells are increased for x > 0.53 due to compression strain and decreased for x < 0.53 due to tensile strain as compared to that of unstrained wells. The calculated band structure parameters are utilized in modeling long channel In0.71Ga0.29As/InP quantum well MOSFETs, and the model is validated against measured I-V and low frequency C-V characteristics at room temperature and cryogenic temperature. Exponential band tails and first- and second-order variation of the charge centroid capacitance and interface trap density are included in the electrostatic model. The Urbach parameter obtained in the model is E-0 = 9 meV, which gives subthreshold swing (SS) of 18 mV/dec at T = 13 K and agrees with the measured SS of 19 mV/dec. Interface trap density is approximately three orders higher at T = 300 K compared to T = 13 K due to multi-phonon activated traps. This model emphasizes the importance of considering disorders in the system in developing device simulators for cryogenic applications. (C) 2022 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/)