Bulk and surface effects of hydrogen treatment on Al/Ti-gate AlGaAs-GaAs power HFETs

Gaddi, R.; Menozzi, Roberto; Dieci, D.; Lanzieri, C.; Meneghesso, Gaudenzio; Canali, C.; Zanoni, Enrico

doi:10.1109/relphy.1999.761601

Cited by 6 publications

(8 citation statements)

References 19 publications

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“…1, does not recover with further N annealing. All these results are consistent with similar experiments reported in AlGaAs/GaAs HEMTs [7]. Devices without Si N passivation were also fabricated and underwent identical experiments.…”

Section: Resultssupporting

confidence: 89%

“…Unlike and , the change in is nonrecoverable. These results are consistent with similar experiments reported in AlGaAs/GaAs HEMTs [7].…”

Section: Introductionsupporting

confidence: 93%

“…This could change the surface Fermi-pinning position or result in trap states that can subsequently become occupied by electrons. Both would be consistent with a reduction in [7], [11]. Moreover, this phenomenon is logically not recoverable, consistent with both the XPS and electrical experiments.…”

Section: Resultssupporting

confidence: 69%

“…A change in the surface potential of the exposed InAlAs could come about through As desorption, leaving behind a cation rich surface [10]. This mechanism can reduce by changing the Fermi level pinning position at the surface [11] or by creating trap states that become subsequently occupied [7]. Fig.…”

Section: Resultsmentioning

confidence: 99%

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Hydrogen-induced changes in the breakdown voltage of InP HEMTs

Blanchard

Alamo

Calveras

2005

IEEE Trans. Device Mater. Relib.

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Abstract-In this work, electrical measurements show that the breakdown voltage, BV DG , of InP HEMTs increases following exposure to H 2 . This BV DG shift is nonrecoverable. The increase in BV DG is found to be due to a decrease in the carrier concentration in the extrinsic portion of the device. We provide evidence that H 2 reacts with the exposed InAlAs surface in the extrinsic region next to the gate, changing the underlying carrier concentration. Hall measurements of capped and uncapped HEMT samples show that the decrease in sheet carrier concentration can be attributed to a modification of the exposed InAlAs surface. Consistent with this, XPS experiments on uncapped heterostructures give evidence of As loss from the InAlAs surface upon exposure to hydrogen.

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Section: Resultssupporting

confidence: 89%

“…Unlike and , the change in is nonrecoverable. These results are consistent with similar experiments reported in AlGaAs/GaAs HEMTs [7].…”

Section: Introductionsupporting

confidence: 93%

Section: Resultssupporting

confidence: 69%

Section: Resultsmentioning

confidence: 99%

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Hydrogen-induced changes in the breakdown voltage of InP HEMTs

Blanchard

Alamo

Calveras

2005

IEEE Trans. Device Mater. Relib.

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“…Hydrogen is typically out-gassed from hermetic packaging materials, or it can be left over from PECVD dielectric deposition [20]. The main effect of hydrogen is its reaction with the Ti metal to form TiH [9].…”

Section: Gatementioning

confidence: 99%

Electrical degradation mechanisms of RF power GaAs PHEMTs

Villanueva

Alamos

Hisaka³

et al.

IEEE International Electron Devices Meeting 2003

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GaAs Pseudomorphic High-Electron Mobility Transistors (PHEMTs) are widely used in RF power applications. Since these devices typically operate at high power levels and under high voltage biasing, their electrical reliability is of serious concern. Previous studies have identified several distinct degradation phenomena in these devices, but a complete picture has yet to be formed.In this study, we have carried out a comprehensive study of the mechanisms of electrical degradation on a set of experimental RF power GaAs PHEMTs (non-commercial devices provided by our sponsor, Mitsubishi Electric). A wide variety of electrical stressing experiments employing different conditions (varying temperature, bias, environment) were performed on these devices in order to monitor their degradation with stressing.Our general observations showed several forms of degradation, the most concerning being an increase in the drain resistance RD and a reduction in maximum drain current Ima. Contrary to what is often claimed in the literature, our experiments indicated that these forms of degradation were not driven by impact-ionization or hot-electron effects. Instead, we found the degradation to be strongly correlated with temperature, stressing environment, and drain-gate bias, which were all consistent with a corrosion mechanism. Via materials analysis we were able to confirm that the degradation of both RD and I,., were due to surface corrosion on the drain side of the device, albeit at different specific locations. The increase in RD was attributed to oxidation on the n+GaAs ledge, while the reduction in I, was due to oxidation on the AlGaAs surface, closer to the gate.A recoverable negative shift in the threshold voltage VT and a permanent decrease in Rs were also observed during electrical stressing. The shift in VT was attributed to field-assisted tunneling of electrons out of traps under the gate, while the decrease in Rs was found to be consistent with recombination-induced annealing of defects on the source side of the device.

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