Electron mobility in the linear region of an AlGaN/AlN/GaN heterostructure field-effect transistor

We simulate the current-voltage(I-V) characteristics of AlGaN/AlN/GaN heterostructure field-effect transistors(HFETs) with different gate lengths using the quasi-two-dimensional(quasi-2D) model.The calculation results obtained using the modified mobility model are found to accord well with the experimental data.By analyzing the variation of the electron mobility for the two-dimensional electron gas(2DEG) with the electric field in the linear region of the AlGaN/AlN/GaN HFET I-V output characteristics,it is found that the polarization Coulomb field scattering still plays an important role in the electron mobility of AlGaN/AlN/GaN HFETs at the higher drain voltage and channel electric field.As drain voltage and channel electric field increase,the 2DEG density reduces and the polarization Coulomb field scattering increases,as a result,the 2DEG electron mobility decreases.