TMAH-based wet surface pre-treatment for reduction of leakage current in AlGaN/GaN MIS-HEMTs

Yoon, Young Jun; Seo, Jae Hwa; Cho, Min Su; Kang, Hoyoul; Won, Chul-Ho; Kang, In Man; Lee, Jung‐Hee

doi:10.1016/j.sse.2016.06.009

Cited by 27 publications

(13 citation statements)

References 23 publications

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“…Thus, the TMAH-based treatment process influences the removal of native Ga-oxide and enhances the surface roughness [ 19 ]. In a previous study, we also confirmed that the TMAH treatment reduced the leakage current characteristics by effectively removing surface states on the GaN cap layer [ 14 ]. To investigate effects of the pre-treatment on the surface, we set the treatment time as 0, 1, and 3 min.…”

Section: Device Structure and Fabricationsupporting

confidence: 81%

“…The pre-treatment processes before the deposition passivation layer were applied to improve the performances of GaN-based devices. In SiN-passivated devices, the pre-treatment process is based on Tetramethylammonium(TMAH) [ 14 ], NH 3 [ 15 ], H 2 SO 4 [ 16 ] solutions, and N 2 plasma [ 17 ] to enhance SiN/(Al)GaN interface quality because the interface quality affects device performance and reliability. The current collapse characteristics of the AlGaN/GaN heterojunction-based devices can be especially degraded by the surface state of the (Al)GaN layer.…”

Section: Introductionmentioning

confidence: 99%

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Effects of Proton Irradiation on the Current Characteristics of SiN-Passivated AlGaN/GaN MIS-HEMTs Using a TMAH-Based Surface Pre-Treatment

et al. 2021

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This study investigated the combined effects of proton irradiation and surface pre-treatment on the current characteristics of Gallium Nitride (GaN)-based metal-insulator-semiconductor high-electron-mobility-transistors (MIS-HEMTs) to evaluate the radiation hardness involved with the Silicon Nitride (SiN) passivation/GaN cap interface. The impact of proton irradiation on the static and dynamic current characteristics of devices with and without pre-treatment were analyzed with 5 MeV proton irradiation. In terms of transfer characteristics before and after the proton irradiation, the drain current of the devices without and with pre-treatment were reduced by an increase in sheet and contact resistances after the proton irradiation. In contrast with the static current characteristics, the gate-lag characteristics of the device with pre-treatment were significantly degenerated. In the device with pre-treatment, the hydrogen passivation for surface states of the GaN cap was formed by the pre-treatment and SiN deposition processes. Since the hydrogen passivation was removed by the proton irradiation, the newly created vacancies resulted in the degeneration of gate-lag characteristics. After nine months in an ambient atmosphere, the gate-lag characteristics of the device with pre-treatment were recovered because of the hydrogen recombination. These results demonstrated that the radiation hardness of MIS-HEMTs was affected by the SiN/GaN interface quality.

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Section: Device Structure and Fabricationsupporting

confidence: 81%

Section: Introductionmentioning

confidence: 99%

Effects of Proton Irradiation on the Current Characteristics of SiN-Passivated AlGaN/GaN MIS-HEMTs Using a TMAH-Based Surface Pre-Treatment

et al. 2021

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“…The leakage current density of optimized SBD is ∼10 −9 A/cm 2 @10 V and 10 −5 A/cm 2 @50 V, which is three orders of magnitude lower than that of the reference, as well. Leakage current along the sidewall is one of the main leakage path for quasi-vertical GaN SBD, as ICP dry etch might create surface damage (e.g., N vacancies) [28], [29]. Therefore, post-mesa nitridation technique has been developed to remove the sidewall damage and then reduce the leakage.…”

Section: Resultsmentioning

confidence: 99%

“…7, the native oxide was removed by dry etch while the nitrogen vacancy (V N ) was formed near the etched surface. A large amount of V N was introduced as donor-like traps, resulting in the band bending and the increase of surface state density of the etched GaN [34]. The traps will create a primary path for leakage current along the etched mesa sidewall.…”

Section: Resultsmentioning

confidence: 99%

Low Leakage and High Forward Current Density Quasi-Vertical GaN Schottky Barrier Diode With Post-Mesa Nitridation

Kang

Sun

Zheng

et al. 2021

IEEE Trans. Electron Devices

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In this brief, a high-performance quasi-vertical GaN Schottky barrier diode (SBD) on sapphire substrate with post-mesa nitridation process is reported, featuring a low damaged sidewall with extremely low leakage current. The fabricated SBD with a drift layer of 1 μm has achieved a very high ON/OFF current ratio (I ON /I OFF ) of 10 12 with a low leakage current of ∼10 −9 A/cm 2 @-10 V, high forward current density of 5.2 kA/cm 2 at 3 V in dc, a low differential specific ON-resistance (R ON,sp ) of 0.3 m•cm 2 , and ideality factor of 1.04. In addition, a transmission-line-pulse (TLP) I-V test was carried out and 53 kA/cm 2 at 30 V in pulsed measurement was obtained without device failure, exhibiting a great potential for high power applications.

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“…Furthermore, the TMAH solution was used to reduce the plasma etch damage on the fin sidewalls. It has been reported that, to create a clean surface, the TMAH solution process considerably reduces surface leakage currents by eliminating the defects on the GaN surface [7,18]. As a result, the fabricated device showed low gate leakage current characteristics as can be seen in the inset of figure 3.…”

Section: Device Characteristics and Discussionmentioning

confidence: 93%

Fabrication of AlGaN/GaN Fin-Type HEMT Using a Novel T-Gate Process for Improved Radio-Frequency Performance

et al. 2020

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To increase the radio-frequency (RF) performance of AlGaN/GaN-based fin-type high electron mobility transistors (HEMTs), a novel T-gate process was developed and applied to fabricate a device with high RF performance. In a single lithography process, the applied T-gate process shows a technique for forming a T-gate using the reactivity difference of several photoresists. The fabricated device has a steep fin width (Wfin) of 130 nm, a fin height (Hfin) of 250 nm, and a gate length (LG) of 190 nm. The device exhibits a low leakage current (Ioff) of 6.6 × 10 −10 A/mm and a high Ion/Ioff current ratio of 4.7 × 10 8. Moreover, the fabricated device achieved a high cut-off frequency (fT) of 9.7 GHz and a very high maximum oscillation frequency (fmax) of 27.8 GHz. The fmax value of the proposed device is 138% higher than that of GaN-based fin-type HEMTs without T-gate.

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TMAH-based wet surface pre-treatment for reduction of leakage current in AlGaN/GaN MIS-HEMTs

Cited by 27 publications

References 23 publications

Effects of Proton Irradiation on the Current Characteristics of SiN-Passivated AlGaN/GaN MIS-HEMTs Using a TMAH-Based Surface Pre-Treatment

Effects of Proton Irradiation on the Current Characteristics of SiN-Passivated AlGaN/GaN MIS-HEMTs Using a TMAH-Based Surface Pre-Treatment

Low Leakage and High Forward Current Density Quasi-Vertical GaN Schottky Barrier Diode With Post-Mesa Nitridation

Fabrication of AlGaN/GaN Fin-Type HEMT Using a Novel T-Gate Process for Improved Radio-Frequency Performance

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