Radiation hardness of AlGaN/GaN based HEMTs
- PDF / 269,737 Bytes
- 6 Pages / 595 x 842 pts (A4) Page_size
- 58 Downloads / 210 Views
Radiation hardness of AlGaN/GaN based HEMTs S.A.Vitusevich1*, N.Klein1, A.E.Belyaev2, S.V.Danylyuk1,2, M.V.Petrychuk2, R.V.Konakova2, A.M.Kurakin2, A.E.Rengevich2, A.Yu.Avksentyev2, B.A.Danilchenko3, V.Tilak4, J.Smart4, A.Vertiatchikh4, and L.F.Eastman4 1 Institut für Schichten und Grenzflächen, Forschungszentrum Jülich, Jülich 52425, Germany 2 Institute of Semiconductor Physics, NASU, Kiev 03028, Ukraine 3 Institute of Physics, NASU, Kiev 03028, Ukraine 4 School of Electrical Engineering, Cornell University, Ithaca, New York 14853 ABSTRACT In this work we present steady-state characteristics and low-frequency noise spectra of AlGaN/GaN based high electron mobility transistors (HEMTs) exposed to gamma ray radiation. The devices with a variety of gate length (150-350 nm) and width (100-400 µm) were irradiated by 60Co gamma rays with doses in the range of 104-109 Rad and flux of 102 Rad/s. Dose dependencies of basic operating parameters of the transistors, such as saturation current (Isat), transconductance (gm), channel conductance (gc), and threshold voltage (VT) are analysed. Our study show that visible changes of above mentioned parameters are observed under relatively small doses (105 Rad) and strongly depend on the HEMT’s topology. The transconductance decreases and threshold voltage becomes more negative for all devices while deviation of these parameters from its initial values does not exceed 20% at highest irradiation dose. At the same time variation of the channel conductance as well as saturation current depends to a high extent on the gate voltage (Vg). At |Vg| < |Vcr|, both Isat and gc show a reversal proportional to the cumulative dosage of radiation. However, at |Vg| > |Vcr|, drain saturation current and channel conductance increase with the cumulative dosage of radiation. The effect is more pronounced in short-length-gate devices. INTRODUCTION Wide band-gap heterojunctions based on AlGaN/GaN structures appear to be very promising for high power and radiation resistant microwave devices including high electron mobility transistors (HEMTs). To realise the excellent potential of Group III-Nitride compound semiconductors for high temperature, high frequency, and high power microwave applications there is a need for physical models describing the device performance and reliability. One of the main issues to be considered is the influence of defects arising under various treatments (in particular, irradiation) on charge carriers transport in such devices. This is because of expectation of their operation in hard radiation environment. Recent studies have shown sufficient radiation tolerance of Group III-Nitride compound semiconductors [1-5]. At the same time, information concerning to dc and rf performance of AlGaN/GaN based HEMTs subjected to different kinds of radiation is restricted to a few reports [6-9]. Moreover, there is nothing known of noise sources in irradiated devices, while noise analysis can be used as a diagnostic tool not only for improving device performance, but also for obtaining substant
Data Loading...
