Influence of the ratio of gate length to drain-to-source distance on the electron mobility in AlGaN/AlN/GaN heterostructure field-effect transistors
1 School of Physics, Shandong University, Jinan, 250100, China
2 Science and Technology on ASIC Laboratory, Hebei Semiconductor Research Institute, Shijiazhuang, 050051, China
3 Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China
Nanoscale Research Letters 2012, 7:434 doi:10.1186/1556-276X-7-434Published: 3 August 2012
Using measured capacitance-voltage curves with different gate lengths and current–voltage characteristics at low drain-to-source voltage for the AlGaN/AlN/GaN heterostructure field-effect transistors (HFETs) of different drain-to-source distances, we found that the dominant scattering mechanism in AlGaN/AlN/GaN HFETs is determined by the ratio of gate length to drain-to-source distance. For devices with small ratio (here, less than 1/2), polarization Coulomb field scattering dominates electron mobility. However, for devices with large ratio (here, more than 1/2), longitudinal optical (LO) phonon scattering and interface roughness scattering are dominant. The reason is closely related to polarization Coulomb field scattering.