We present an extensive analysis of the trapping processes induced by drain bias stress in AlGaN/GaN high-electron-mobility transistors (HEMTs) with p-GaN gate. We demonstrate that: (i) with increasing drain stress, pulsed I-V and VTH measurements shown an initial positive VTH variation and an increase in RON then, for drain voltages >100 V, VTH is stable and the RON shows a partial recovery. (ii) At moderate voltages, VTH instability is related to trapping at the gate stack, due to residual negative charge left behind by the holes that leave the p-GaN layer through the Schottky gate contact and/or to trapping at the barrier. At higher voltages, we demonstrate the interplay of two trapping processes by C[sbnd]V and pulsed drain current analysis: (iii) a fast storage of positive charge, accumulated near the buffer/SRL interface, not strongly thermally activated, dominating at higher voltages; (iv) a slower negative charge storage, thermally activated with activation energies for trapping and de-trapping equal to ~0.6 eV and ~0.4–0.8 eV, respectively.

OFF-state trapping phenomena in GaN HEMTs: Interplay between gate trapping, acceptor ionization and positive charge redistribution

Canato E.;Meneghini M.;De Santi C.;Masin F.;Zanoni E.;Meneghesso G.
2020

Abstract

We present an extensive analysis of the trapping processes induced by drain bias stress in AlGaN/GaN high-electron-mobility transistors (HEMTs) with p-GaN gate. We demonstrate that: (i) with increasing drain stress, pulsed I-V and VTH measurements shown an initial positive VTH variation and an increase in RON then, for drain voltages >100 V, VTH is stable and the RON shows a partial recovery. (ii) At moderate voltages, VTH instability is related to trapping at the gate stack, due to residual negative charge left behind by the holes that leave the p-GaN layer through the Schottky gate contact and/or to trapping at the barrier. At higher voltages, we demonstrate the interplay of two trapping processes by C[sbnd]V and pulsed drain current analysis: (iii) a fast storage of positive charge, accumulated near the buffer/SRL interface, not strongly thermally activated, dominating at higher voltages; (iv) a slower negative charge storage, thermally activated with activation energies for trapping and de-trapping equal to ~0.6 eV and ~0.4–0.8 eV, respectively.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11577/3365234
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