Influence of polarization on the properties of GaN based FET structures

GaN is the first highly polar semiconductor used in field effect transistors. Polarization charge dipoles are an essential part contributing to the device performance. Especially at the surface such charges may influence stability and large signal characteristics. Switching transients in output current of AlGaN/GaN‐FETs related to charge storage effects are discussed and related to the polar nature of this material system. Alternative structures not suffering of the surface charge problem are introduced, namely an InGaN‐channel FET and a AlGaN/GaN‐double barrier structure. For realization doping screening of the polarization field is applied as main tool. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)