Impact of surface treatment under the gate on the current collapse of unpassivated AlGaN/GaN heterostructure field-effect transistors
English
Kordoš, P.[Institute of Electrical Engineering, Slovak Academy of Sciences, SK-84104 Bratislava, Slovak Republic, and Department of Microelectronics, Slovak University of Technology, SK-81219 Bratislava, Slovak Republic]
Bernát, J.[Institute of Thin Films and Interfaces and cni - Center of Nanoelectronic Systems for Information Technology, Research Centre Jülich, 52425 Jülich, Germany]
Gregušová, D.[Institute of Electrical Engineering, Slovak Academy of Sciences, SK-84104 Bratislava, Slovak Republic]
Marso, Michel[Institute of Thin Films and Interfaces and cni - Center of Nanoelectronic Systems for Information Technology, Research Centre Jülich, 52425 Jülich, Germany]
Lüth, H.[Institute of Thin Films and Interfaces and cni - Center of Nanoelectronic Systems for Information Technology, Research Centre Jülich, 52425 Jülich, Germany]
[en] Unpassivated GaN/AlGaN/GaN/SiC heterostructure field-effect transistors were fabricated on intentionally undoped and 5 × 1018 cm−3 modulationdoped material structures. The influence of surface treatment before gate metallization on the gate leakage and drain current collapse of the devices was observed. In the case of a short HCl treatment (∼5 s), a relatively small gate leakage (<10−6A mm−1 at −6 V gate bias) but large current collapse (∼30% after applying 5 μs wide pulses) were measured. On the other hand, devices with a longer surface treatment (15–20 s) showed an increased gate leakage (>10−4A mm−1) and a simultaneously negligible current collapse (<5%). This effect is qualitatively similar in devices prepared on the undoped and doped heterostructures. It is assumed that a thin interfacial oxide layer under the gate might be responsible for a lower leakage current and a larger current collapse of the devices.
[Institute of Thin Films and Interfaces and cni - Center of Nanoelectronic Systems for Information Technology, Research Centre Jülich, 52425 Jülich, Germany]
