p-GaN Gate HEMTs With Tungsten Gate Metal for High Threshold Voltage and Low Gate Current

Hwang, In-Sun; Kim, Jongseob; Choi, Hyuk Soon; Choi, Hongseok; Lee, Jaewon; Kim, Kyung Yeon; Park, Jong-Bong; Lee, Jae Cheol; Ha, Jong‐Bong; Oh, Jaejoon; Shin, Jaikwang; Chung, U‐In

doi:10.1109/led.2012.2230312

Cited by 222 publications

(87 citation statements)

References 7 publications

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“…So far, there are several approaches to realize an enhancement mode operation, such as a recessed gate structure [1] [2], p-GaN gate [3][4] [5], p-AlGaN gate [6], fluoride-based plasma treatment [7], the piezoneutralization layer [8], and floating charges [9], etc. Among these different approaches, the AlGaN/GaN HEMT with either a p-GaN or p-AlGaN gate is a promising candidate for an enhancement mode device.…”

Section: Introductionmentioning

confidence: 99%

Forward Bias Gate Breakdown Mechanism in Enhancement-Mode p-GaN Gate AlGaN/GaN High-Electron Mobility Transistors

Marcon

You

et al. 2015

IEEE Electron Device Lett.

170

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In this work, we studied the forward bias gate breakdown mechanism on Enhancement-mode p-GaN gate AlGaN/GaN HEMTs. To the best of our knowledge, it is the first time that the temperature dependency of the forward gate breakdown has been characterized. We report for the first time on the observation of a positive temperature dependency, i. e., a higher temperature leads to a higher gate breakdown voltage. Such unexpected behavior is explained by avalanche breakdown mechanism: at a high positive gate bias, electron/hole pairs are generated in the depletion region at the Schottky metal/p-GaN junction. Furthermore, at a high gate bias but before the catastrophic gate breakdown, a light emission was detected by a emission microscopy measurement (EMMI). This effect indicates an avalanche luminescence, which is mainly due to the recombination of the generated electron/hole pairs. Index Terms-p-GaN, AlGaN/GaN HEMTs, Forward bias gate breakdown, avalanche breakdown.

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Section: Introductionmentioning

confidence: 99%

Forward Bias Gate Breakdown Mechanism in Enhancement-Mode p-GaN Gate AlGaN/GaN High-Electron Mobility Transistors

Marcon

You

et al. 2015

IEEE Electron Device Lett.

170

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“…An E-mode device with a high breakdown voltage of 1600 V was proposed in [12] using a total epi thickness of 5.2 μm. Tungsten was used to replace nickel as the gate metal in [13] to increase the V th to 3 V and decrease the gate current density to 0.02 mA/mm at a gate bias of 10 V. An E-mode and low-current collapse device was conceived in [14] using a p-GaN gate, NH 3 surface treatment, and a high temperature oxide passivation layer. In these studies, nickel and tungsten were used to form contact to the p-GaN gate, but the p-GaN ohmic contacts are rather difficult to form if not properly treated [15]- [17].…”

Section: Introductionmentioning

confidence: 99%

Phenomenon of Drain Current Instability on p-GaN Gate AlGaN/GaN HEMTs

Chang

Hsiao

Chen

et al. 2015

IEEE Trans. Electron Devices

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In this paper, an observation of drain current instability on p-GaN gate AlGaN/GaN HEMTs is reported. Contrary to the Schottky gate AlGaN/GaN HEMTs, which show stable and consistent I d -V d curves under different pulsed conditions, the I d -V d curves for p-GaN gate AlGaN/GaN HEMTs show a dispersion in the saturation region under the same pulse conditions, which cannot be explained by the trapping of electrons in the material. A model considering the trapping of holes in the p-GaN gate under different gate and drain biases is proposed to explain this new phenomenon.

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“…This can be implemented by recessing the AlGaN Schottky barrier layer or using a fluorine-based plasma surface treatment to eliminate the two dimensional electron gas (2DEG), under the gate region [5], [6]. Another technique is to grow a p-GaN or p-AlGaN layer on top of the Schottky barrier layer to deplete the 2DEG underneath [7]- [9]. In this letter, we propose a new device epi-structure demonstrating normally-off operation, owing to the net negative polarization charge generated by combining an AlGaN/GaN/AlGaN This paragraph of the first footnote will contain the date on which you submitted your paper for review.…”

Section: Introductionmentioning

confidence: 99%

Normally-Off AlGaN/GaN/AlGaN Double Heterostructure FETs With a Thick Undoped GaN Gate Layer

Benkhelifa

Müller

Polyakov

et al. 2015

IEEE Electron Device Lett.

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In this letter, we report on polarization charge engineering enabling normally-off operation for a doubleheterostructure Al 0.26 Ga 0.74 N/GaN/Al 0.07 Ga 0.93 N-based field effect transistors (DHFETs) using a 35 nm thick undoped GaN layer underneath the gate metallization. The combined effect of the negative polarization charge induced by the AlGaN back barrier and the undoped GaN gate layer ensures the total depletion of the channel, and provides a positive threshold voltage. The fabricated DHFET exhibits normally-off operation with a threshold voltage of +1.2 V, a maximum drain current density of 370 mA/mm, and a high ON/OFF current ratio of 10 7 , at a gate bias of +7 V. A transistor with gate-drain distance of 6 µm demonstrates 300 V off-state breakdown voltage. Index Terms-Normally-off, AlGaN/GaN/AlGaN DHFET, AlGaN back-barrier, thick undoped GaN gate layer, polarization charge engineering.

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p-GaN Gate HEMTs With Tungsten Gate Metal for High Threshold Voltage and Low Gate Current

Cited by 222 publications

References 7 publications

Forward Bias Gate Breakdown Mechanism in Enhancement-Mode p-GaN Gate AlGaN/GaN High-Electron Mobility Transistors

Forward Bias Gate Breakdown Mechanism in Enhancement-Mode p-GaN Gate AlGaN/GaN High-Electron Mobility Transistors

Phenomenon of Drain Current Instability on p-GaN Gate AlGaN/GaN HEMTs

Normally-Off AlGaN/GaN/AlGaN Double Heterostructure FETs With a Thick Undoped GaN Gate Layer

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