Influence of carrier supply doping on the RF properties of AlGaN/GaN/SiC high-electron-mobility transistors
English
Marso, Michel[Institute of Thin Films and Interfaces (ISG1) and cni - Center of Nanoelectronic Systems for Information Technology, Research Centre Jülich, 52425 Jülich, Germany]
Bernát, J.[Institute of Thin Films and Interfaces (ISG1) and cni - Center of Nanoelectronic Systems for Information Technology, Research Centre Jülich, 52425 Jülich, Germany]
Javorka, P.[Institute of Thin Films and Interfaces (ISG1) and cni - Center of Nanoelectronic Systems for Information Technology, Research Centre Jülich, 52425 Jülich, Germany]
Fox, A.[Institute of Thin Films and Interfaces (ISG1) and cni - Center of Nanoelectronic Systems for Information Technology, Research Centre Jülich, 52425 Jülich, Germany]
Kordoš, P.[Institute of Thin Films and Interfaces (ISG1) and cni - Center of Nanoelectronic Systems for Information Technology, Research Centre Jülich, 52425 Jülich, Germany]
[en] We have fabricated undoped as well as modulation-doped AlGaN/GaN HEMTs on SiC substrate. The influence of the carrier supply layer on device performance is investigated by Hall, channel conductivity, small signal RF and delay time evaluation. While the doping layer improves the DC performance it degrades the RF behaviour of the device with the highest carrier supply doping of 5x1018 cm–3. The channel conductivity measurements show identical dependence of the mobility on carrier concentration for all samples. The saturation velocity, extracted by evaluation of the total delay time as function of the inverse drain current, decreases from 0.86x107 cm/s for the undoped device to 0.7x107 cm/s for the highest doped HEMT. This result shows that the degradation of RF performance is due to the reduction of the effective saturation velocity caused by the carrier supply layer.
[Institute of Thin Films and Interfaces (ISG1) and cni - Center of Nanoelectronic Systems for Information Technology, Research Centre Jülich, 52425 Jülich, Germany]
