Recess-Free Normally-off GaN MIS-HEMT Fabricated on Ultra-Thin-Barrier AlGaN/GaN Heterostructure

Han, Ping-Cheng; Yan, Zong-Zheng; Wu, Chia-Hsun; Chang, Edward Yi; Ho, Yu-Hsuan

doi:10.1109/ispsd.2019.8757675

Cited by 25 publications

(12 citation statements)

References 15 publications

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“…While, with the post annealing on the NiO x cap layer, the onstate channel current gets evidently enhanced, suggesting the effectiveness of annealing process in enabling the controllability of the p-type gate. The V TH value after nitrogen annealing could be extracted to be ∼0.5 V at the channel current of 1 µA mm −1 [7], corresponding to the preliminary accumulation of the 2DEG channel. This value agrees well with the theoretical calculation results from equation ( 3), verifying the calculation methology established for the p-NiO x gated GaN HEMT.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Current transport dynamics and stability characteristics of the NiO _x based gate structure for normally-off GaN HEMTs

Du¹,

Xu²,

Gong³

et al. 2022

J. Phys. D: Appl. Phys.

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The application of p-type oxide typified with NiOx as cap layer in AlGaN/GaN HEMT for normally-off operation has specific benefits, including etching free fabrication process, high hole density and elimination of Mg dopants diffusion effects. This work presents a device configuration exploration combining the p-NiOx gate cap layer and a thin AlGaN barrier layer. Calculation method for the threshold voltage has been discussed, which obtains good consistence with the experimental measurements. In addition, a nitrogen based post-annealing process was developed to improve the film stoichiometry for elevated gate controllability, realizing normally-off operation with enhanced channel conduction capability. The current transport dynamics in the gate stack as coupled with the NiOx/AlGaN interface states have also been studied, where a deep level trap was recognized in dominating the gate current characteristics and the gate stability performance under different forward gate bias conditions.

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Section: Resultsmentioning

confidence: 99%

“…thin AlGaN barrier [7][8][9] and cascode structure with Si MOS-FET. The p-GaN gated structure has been commercially adopted owing to its excellent balance between device performance and reliability [10].…”

Section: Introductionmentioning

confidence: 99%

Current transport dynamics and stability characteristics of the NiO _x based gate structure for normally-off GaN HEMTs

Du¹,

Xu²,

Gong³

et al. 2022

J. Phys. D: Appl. Phys.

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“…The conventional GaN HEMT is always depletion mode (D-mode), while the enhancement mode (E-mode) is necessary in power electronics applications. Many structures have been proposed to achieve the E-mode, such as a thinned AlGaN barrier layer [5], p-gate structure [6], recessed gate structure [7], and fluoride ion treatment [8,9]. All technologies above are realized by depleting the 2DEG under the gate, inevitably encountering a tradeoff between a high threshold voltage (V th ) and a large saturated output current (I d, sat ).…”

Section: Introductionmentioning

confidence: 99%

High Performance Flip-Structure Enhancement-Mode HEMT with Face-to-Face Double Gates

et al. 2022

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A novel double gates flip-structure enhancement-mode (E-mode) high electron mobility transistor with step field plate (DFF HEMT) is proposed. It features face-to-face double gates, including a top trench MIS gate with a step field plate and a bottom planar MIS gate, which is shorted together. In the on-state, the double gates not only can restore the 2DEG by the higher electric potential, but also can form the electron accumulation layers, and thus increase the saturation output current and reduce the on-resistance. The face-to-face double gates together deplete the 2DEG by using the work function difference to realize E-mode, instead of by etching the AlGaN layer under the gate for the conventional MIS gate E-mode HEMT. The double-gate structure not only avoids etch damage, but also maintains both high threshold voltage and low on-resistance. Meanwhile, the step gate field plate modulates E-field distribution to increase the BV. In order to easily fabricate, the trench gate with step field plate must be located on the top of device, forming the flip-structure. The flip-structure is also beneficial to decrease the leakage current in the substrate. The simulated Vth, BV and Id of the DFF HEMT are 0.8 V, 465 V and 494 mA/mm, respectively. The FOM of the DFF HEMT is 79.8% and 444.2% higher than those of the conventional MIS-FP HEMT and MIS HEMT.

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“…[3] The technology of the E-mode GaN HEMTs has been fully studied. [4][5][6] In the past, the challenges of the GaN-based E-mode HEMTs are mainly focused in the trade-off between large output current and positive threshold. [6] Although a large current of 1.9 A/mm with a threshold of 0.8 V and a threshold of 4.6 V with a low current of 4.4 mA/mm have been achieved respectively in Refs.…”

Section: Introductionmentioning

confidence: 99%

High-frequency enhancement-mode millimeterwave AlGaN/GaN HEMT with an f _T/f _max over 100 GHz/200 GHz*

Wu¹,

Mi²,

Ma³

et al. 2021

Chinese Phys. B

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Ultra-thin barrier (UTB) 4-nm-AlGaN/GaN normally-off high electron mobility transistors (HEMTs) having a high current gain cut-off frequency (f T) are demonstrated by the stress-engineered compressive SiN trench technology. The compressive in-situ SiN guarantees the UTB-AlGaN/GaN heterostructure can operate a high electron density of 1.27 × 1013 cm−2, a high uniform sheet resistance of 312.8 Ω/□, but a negative threshold for the short-gate devices fabricated on it. With the lateral stress-engineering by full removing in-situ SiN in the 600-nm SiN trench, the short-gated (70 nm) devices obtain a threshold of 0.2 V, achieving the devices operating at enhancement-mode (E-mode). Meanwhile, the novel device also can operate a large current of 610 mA/mm and a high transconductance of 394 mS/mm for the E-mode devices. Most of all, a high f T/f max of 128 GHz/255 GHz is obtained, which is the highest value among the reported E-mode AlGaN/GaN HEMTs. Besides, being together with the 211 GHz/346 GHz of f T/f max for the D-mode HEMTs fabricated on the same materials, this design of E/D-mode with the realization of f max over 200 GHz in this work is the first one that can be used in Q-band mixed-signal application with further optimization. And the minimized processing difference between the E- and D-mode designs the addition of the SiN trench, will promise an enormous competitive advantage in the fabricating costs.

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Recess-Free Normally-off GaN MIS-HEMT Fabricated on Ultra-Thin-Barrier AlGaN/GaN Heterostructure

Cited by 25 publications

References 15 publications

Current transport dynamics and stability characteristics of the NiO _x based gate structure for normally-off GaN HEMTs

Current transport dynamics and stability characteristics of the NiO _x based gate structure for normally-off GaN HEMTs

High Performance Flip-Structure Enhancement-Mode HEMT with Face-to-Face Double Gates

High-frequency enhancement-mode millimeterwave AlGaN/GaN HEMT with an f _T/f _max over 100 GHz/200 GHz*

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Recess-Free Normally-off GaN MIS-HEMT Fabricated on Ultra-Thin-Barrier AlGaN/GaN Heterostructure

Cited by 25 publications

References 15 publications

Current transport dynamics and stability characteristics of the NiO x based gate structure for normally-off GaN HEMTs

Current transport dynamics and stability characteristics of the NiO x based gate structure for normally-off GaN HEMTs

High Performance Flip-Structure Enhancement-Mode HEMT with Face-to-Face Double Gates

High-frequency enhancement-mode millimeterwave AlGaN/GaN HEMT with an f T/f max over 100 GHz/200 GHz*

Contact Info

Product

Resources

About

Current transport dynamics and stability characteristics of the NiO _x based gate structure for normally-off GaN HEMTs

Current transport dynamics and stability characteristics of the NiO _x based gate structure for normally-off GaN HEMTs

High-frequency enhancement-mode millimeterwave AlGaN/GaN HEMT with an f _T/f _max over 100 GHz/200 GHz*