A review of failure modes and mechanisms of GaN-based HEMTs

Zanoni, Enrico; Meneghesso, G.; Verzellesi, Giovanni; Danesin, F.; Meneghini, Matteo; Rampazzo, F.; Tazzoli, Augusto; Zanon, Franco

doi:10.1109/iedm.2007.4418952

Cited by 41 publications

(24 citation statements)

References 3 publications

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“…Decrease in output power and power added efficiency as a consequence of device knee-walkout and gate current degradation are amongst the most deleterious effects that can arise during device operation [3,4]. Zanoni et al [5] have shown that high reverse biases can result in the formation of defects located at the edge of the gate contact.…”

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confidence: 99%

Evaluation of GaN HEMT degradation by means of pulsed I–V, leakage and DLTS measurements

et al. 2009

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The effects of short-term step-stress on the performance of GaN HEMTs have been evaluated for the first time by means of current deep-leveltransient-spectroscopy (DLTS) measurements. When subjected to high reverse gate bias the devices experienced an increase in the drain current dispersion as well as in the gate current. Current DLTS measurements carried out during the stress experiment show that the device degradation can be associated to the formation of a defect that is thermally activated with an energy of 0.5 eV.Introduction: While the outstanding RF performance of GaN-based high electron mobility transistors has been demonstrated by several authors [1, 2], their reliability still needs to be further improved. Decrease in output power and power added efficiency as a consequence of device knee-walkout and gate current degradation are amongst the most deleterious effects that can arise during device operation [3,4]. Zanoni et al. [5] have shown that high reverse biases can result in the formation of defects located at the edge of the gate contact. These defects have been related to the increase in both reverse currents as well as the device current-collapse. A similar degradation has been also related to defects that are thermally activated with an activation energy of 0.57 eV, as obtained by transient experiments carried out at different temperatures [6]. In this Letter, for the first time, we have studied the degradation of GaN HEMTs subjected to an electrical step-stress sequence by monitoring the formation of defects by means of current deep-level-transient-spectroscopy (DLTS) measurements. At each stress step, electrical parameters such as drain current dispersion, gate leakage and the DLTS signal associated with the defects that are forming during device degradation have been measured. As presented in the following, at the increasing of the reverse voltage applied to the gate Schottky junction we observed an increase in the DC gate leakage current level, an increase in the DLTS signal and larger drain current-collapse.

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confidence: 99%

Evaluation of GaN HEMT degradation by means of pulsed I–V, leakage and DLTS measurements

et al. 2009

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“…It is well known that channel carriers being trapped at the GaN surface can induce some shift of threshold voltage (V T ), Gm max and P out during the ageing test [16,17]. We have checked that this effect was more drastic at 240°C than at 200°C (see Fig.…”

Section: Resultsmentioning

confidence: 94%

A complete methodology for assessing GaN behaviour for military applications

Moreau

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Tence

et al. 2010

Microelectronics Reliability

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“…These defects might be created by the excessive tensile stress on the barrier layer induced by the high bias conditions. The change of surface states induced by trapping effects, metallurgical issues such as metal-semiconductor diffusion, phase changes in metal stacks, and electro-migration within the metal are sources of potential permanent degradation [7,8].…”

Section: Resultsmentioning

confidence: 99%