Low Field Vertical Charge Transport in the Channel and Buffer Layers of GaN-on-Si High Electron Mobility Transistors
| Autor: | Martin Kuball, Ming Zhao, Michael J. Uren, Filip Wach, Benoit Bakeroot, Stefaan Decoutere |
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| Rok vydání: | 2020 |
| Předmět: |
010302 applied physics
Technology and Engineering Materials science Condensed matter physics Doping TRAPS Gallium nitride Charge (physics) AlGaN/GaN HEMT Substrate (electronics) 01 natural sciences Variable-range hopping Electronic Optical and Magnetic Materials vertical charge transport chemistry.chemical_compound chemistry vertical leakage activation barrier 0103 physical sciences Electrical and Electronic Engineering Dislocation DISLOCATIONS Fermi gas Diode |
| Zdroj: | IEEE ELECTRON DEVICE LETTERS |
| ISSN: | 1558-0563 0741-3106 |
| Popis: | Substrate ramps and stepped stress transient measurements are applied to study vertical charge transport mechanisms in GaN-on-Si power HEMTs. By choosing appropriate bias points for substrate stress it is possible to single out the dominant charge transport mechanism: at low negative biases transport through carbon-doped GaN manifests itself in negative (decreasing) current transients with apparent activation energy ( $\text{E}_{\text {A}}) = {0.29}$ eV, while at larger negative voltages transport through unintentionally doped GaN is characterized by positive (increasing) current transients ( $\text{E}_{\text {A}} = {0.38}$ eV). We present experimental evidence for 3D variable range hopping taking place in C-doped GaN and 1D hopping along the dislocations in unintentionally doped GaN. By investigating transients obtained from bidirectional voltage steps of 10 V potential difference in the range 0 to −140 V, we observe that hopping transport through dislocations shows non-Ohmic behavior at low substrate biases, which manifests itself in a time constant $\tau $ strongly dependent on bias. We propose that this can be explained by the existence of a diode junction between the dislocation core and the 2D electron gas (2DEG). |
| Databáze: | OpenAIRE |
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