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

There has been significant advancement in the development of efficient metal oxide semiconductors field effect transistors. Currently, InGaAs alloys have been identified as promising materials for enhancing the performance of the transistors owing to their excellent properties including electron mobility and band gap. Alternatively, recent research has shown that modeling the effective mobility of the InGaAs in the field effect transistor configuration will result in a corresponding development of related applications.

This is attributed to the fact that effective mobility is an important tool in predicting the key parameters of the metal oxide semiconductor field effect transistors such as switching performance and drain current density. Unfortunately, the device parameters influencing the effective mobility have not been fully explored and particularly in modeling the effective mobility of an InGaAs quantum-well metal oxide semiconductor field effect transistor.

To this note, Kyungpook National University researchers: Sethu George, Dr. Seung-woo Son, Professor Jung-Hee Lee and Dr. Dae-Hyun Kim from the School of Electronics Engineering in collaboration with Professor Tae-Woo Kim at the University of Ulsan developed an effective mobility of an In_0.7Ga_0.3As quantum-well metal oxide semiconductor field effect transistor. In particular, they investigated the sources and factors influencing the scattering mechanisms like photon scattering and surface roughness scattering and their overall influence on the performance of the transistors. Their research work is currently published in the research journal, Solid State Electronics.

In brief, the authors commenced their research work by fabricating the field effect transistor using an aluminum oxide gate dielectric layer. Next, the three different scattering mechanisms were modeled separately taking into consideration their respective influence on the vertical electric field intensity so as to verify the application of the Mathiessen’s rule in the scattering mechanisms. Eventually, the overall influence of the scattering mechanism on the effective mobility was analyzed by plotting a graph of the measured scattering components against the electric field intensity.

The research team observed that several factors including temperature, scattering mechanism, interfacial state density and substrate doping concentration affect the effective mobility of the metal oxide semiconductor field effect transistors. The devices exhibited excellent electrostatic integrity with a temperature of 300K and effective mobility of 7000 cm²/ Vs. In addition, it was worth noting that in the low field regime, medium field regime and high field regime, the effective mobility was controlled by the Coulombic scattering, photon scattering, and surface-roughness scattering respectively. Furthermore, Mathiessen’s rule proved effective for analysis the scattering components thus producing consistent results corresponding to the measured effective mobility.

In summary, their study successfully developed scattering effective mobility of an In_0.7Ga_0.3As/In_0.52Al_0.48As quantum-well metal oxide semiconductor field effect transistor using aluminum oxide dielectric layers. In general, their work clarified the various factors and parameters affecting the effective mobility. Therefore, Sethu Merin George and colleagues study will pave way for the design and development of advanced InGaAs as well as InGaAs quantum-well metal oxide semiconductor field effect transistor thus advancing numerous related industries.