Influence of layer structure on performance of AlGaN/GaN high electron mobility transistors before and after passivation

Bernát, J.; Javorka, P.; Fox, A.; Marso, Michel; Kordoš, P.

doi:10.1007/s11664-004-0198-3

Cited by 6 publications

(4 citation statements)

References 18 publications

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“…In agreement with this observation, in our case, we do not see a significant improvement in the DC characteristics of the devices simply due to passivation. This improvement has been observed by other workers (10,11). Typical results from pulsed electrical characterization are shown in Figs.…”

Section: Resultssupporting

confidence: 85%

The Effect of Surface Cleaning on Current Collapse in AlGaN/GaN HEMTs

et al. 2006

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The phenomenon of current collapse is a limiting factor in the performance of AlGaN/GaN high electron mobility transistors (HEMTs), and can be ameliorated by the deposition of a silicon nitride passivation film on the surface. The effect of three types of surface cleaning prior to the application of a silicon nitride passivation layer are studied. The best results were obtained when the wafers were cleaned using an air plasma descum followed by an HCl dip prior to the deposition of the silicon nitride passivation. Auger electron spectroscopy depth profiling indicated that the degree of collapse was correlated with the amount of residual carbon contamination at the silicon nitride/AlGaN interface.

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Section: Resultssupporting

confidence: 85%

The Effect of Surface Cleaning on Current Collapse in AlGaN/GaN HEMTs

et al. 2006

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“…Figure 4 shows the two-terminal gate-source leakage currents that were typical for the undoped and doped GaN/AlGaN/GaN HFETs from both sets. Partially higher leakage currents for the doped devices compared with the undoped ones were expected [15]. However, remarkably higher leakage currents (about four orders of the magnitude) were measured on the longdip-treated devices.…”

Section: Resultsmentioning

confidence: 80%

“…The GaN cap layer was chosen to enhance the effective Schottky barrier height [13,14]. The doping level of 5 × 10 18 cm −3 followed from our previous study as an optimal value for modulation-doped GAN HFETs [15].…”

Section: Methodsmentioning

confidence: 99%

Impact of surface treatment under the gate on the current collapse of unpassivated AlGaN/GaN heterostructure field-effect transistors

Kordoš¹,

Bernát²,

Gregušová³

et al. 2005

Semicond. Sci. Technol.

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Unpassivated GaN/AlGaN/GaN/SiC heterostructure field-effect transistors were fabricated on intentionally undoped and 5 × 10 18 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 −6 A 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 −4 A 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.

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“…However, unpassivated AlGaN / GaN HEMTs with low current dispersion were recently presented. [4][5][6][7] Devices prepared on intentionally doped heterostructures were used in these studies. Also, another study reported on improvements in the performance of unpassivated and passivated devices based on a doped material structure compared with the performance of those based on an undoped structure.…”

mentioning

confidence: 99%

Influence of gate-leakage current on drain current collapse of unpassivated GaN∕AlGaN∕GaN high electron mobility transistors

Kordoš

Bernát

Marso

et al. 2005

Applied Physics Letters

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We report on a correlation between the gate leakage currents and the drain current collapse of GaN∕AlGaN∕GaN high electron mobility transistors. Unpassivated devices on intentionally undoped and doped (Si, 5×1018cm−3) heterostructures were investigated. We observed in the devices that the larger the gate leakage current, the smaller the drain current collapse measured at 50ns gate-voltage pulse turn on, and this correlation is independent of the doping of the structure. The correlation holds for two orders of magnitude in the gate-leakage current and up to 15% in drain current collapse. We believe that the leakage current can modulate trapped surface charge so that the time constant of the current collapse becomes much faster and dependent on the amount of leakage current itself.

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Influence of layer structure on performance of AlGaN/GaN high electron mobility transistors before and after passivation

Cited by 6 publications

References 18 publications

The Effect of Surface Cleaning on Current Collapse in AlGaN/GaN HEMTs

The Effect of Surface Cleaning on Current Collapse in AlGaN/GaN HEMTs

Impact of surface treatment under the gate on the current collapse of unpassivated AlGaN/GaN heterostructure field-effect transistors

Influence of gate-leakage current on drain current collapse of unpassivated GaN∕AlGaN∕GaN high electron mobility transistors

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