GaN Vertical-Channel Junction Field-Effect Transistors With Regrown p-GaN by MOCVD

Yang, Chen; Fu, Houqiang; Kumar, Viswanathan Naveen; Fu, Kai; Liu, Hanxiao; Huang, Xuanqi; Yang, Tsung‐Han; Chen, Hong; Zhou, Jingan; Deng, Xuguang; Montes, Jossue; Ponce, Fernando; Vasileska, Dragica; Zhao, Yuji

doi:10.1109/ted.2020.3010183

Cited by 31 publications

(27 citation statements)

References 40 publications

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“…It has recently been recognized that nonuniform dopant incorporation during nonplanar regrowth has a detrimental impact on leakage and breakdown. − A nonplanar regrowth interface includes facets with different bonding geometries, chemical reactivities, and growth rates, leading to an evolving growth interface shape and the potential for nonuniform doping profiles. For example, reduced doping in regrown p-GaN was observed near the sidewalls of UID-GaN mesa structures compared to the top and bottom of the mesa .…”

Section: Introductionmentioning

confidence: 99%

Selective Area Regrowth Produces Nonuniform Mg Doping Profiles in Nonplanar GaN p–n Junctions

Chang

Wang

et al. 2021

ACS Appl. Electron. Mater.

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Nonplanar GaN p–n junctions formed by selective area regrowth were analyzed using pulsed laser atom probe tomography. Dilute Al marker layers were used to map the evolution of the p-GaN growth interface, enabling extraction of time-varying growth rates for nonpolar, semipolar, and polar surfaces from the trench edge to the center, respectively. The Mg dopant concentration is facet-dependent and varies inversely with the growth rate for the semipolar facets that grow rapidly away from the trench sidewalls. The negligible growth on the vertical sidewall of the trench coincides with an order of magnitude higher Mg concentration and substantial clustering of likely inactive dopants. A high Mg concentration is also observed near the regrowth interface of polar and semipolar planes, which we attribute to etching damage. We conclude that device fabrication processes employing selective area regrowth on nonplanar interfaces should consider both the spatial and temporal dependencies of growth rate that lead to nonuniform doping and explore growth conditions that could reduce variations in growth rate when nonuniform doping would adversely affect device performance.

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Section: Introductionmentioning

confidence: 99%

Selective Area Regrowth Produces Nonuniform Mg Doping Profiles in Nonplanar GaN p–n Junctions

Chang

Wang

et al. 2021

ACS Appl. Electron. Mater.

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“…Implant- and diffusion-based selective-area doping (SAD) methods have been actively investigated, − and each faces its respective challenges. Selective-area etching of GaN followed by regrowth or selective-area growth − is intuitively straightforward but has been hampered by the damage and contamination incurred during conventional inductively coupled plasma (ICP) etching. − In the context of etch-and-regrowth, several groups have developed processes to mitigate or repair ICP etching damage with promising results. − Recently, we reported an alternative, in situ etching of GaN with the use of tertiarybutylchloride (TBCl), a Cl-based organometallic precursor. Initial findings indicated that the TBCl etching of GaN has a sufficiently high etch rate and produces minimal damage or contamination. , This etching technique, however, has yet to be tested in working GaN electronic devices.…”

Section: Introductionmentioning

confidence: 99%

Etched-And-Regrown GaN P–N Diodes with Low-Defect Interfaces Prepared by In Situ TBCl Etching

Wang

Nami

et al. 2021

ACS Appl. Mater. Interfaces

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The ability to form pristine interfaces after etching and regrowth of GaN is a prerequisite for epitaxial selective area doping, which in turn is needed for the formation of lateral PN junctions and advanced device architectures. In this work, we report the electrical properties of etched-and-regrown GaN PN diodes using an in situ Cl-based precursor, tertiary butylchloride (TBCl). We demonstrated a regrowth diode with I−V characteristics approaching that from a continuously grown reference diode. The sources of unintentional contamination from the silicon (Si) impurity and the mediating effect of Si during the TBCl etching are also investigated in this study. This work points to the potential of in situ TBCl etching toward the realization of GaN lateral PN junctions.

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“…5(c) and (d), a good linearity was also observed for other γ values between 0.25 and 1, suggesting the need for scrutinizing the physical hopping types in the future work. In previous Fin-JFET reports, a high leakage current is present in the regrown lateral GaN p-n junctions [15], [16], due to the band-to-band tunneling (BTBT) assisted by interfacial defects and impurities [27], [31] [see Fig. 5(b)].…”

Section: B Gate Leakage Current Characteristics and Mechanismsmentioning

confidence: 99%

“…Although a 1.2-kV GaN Fin-JFET was simulated in [14], the experimentally demonstrated devices showed This work is licensed under a Creative Commons Attribution 4.0 License. For more information, see https://creativecommons.org/licenses/by/4.0/ deficient transistor behaviors with minimal voltage-blocking capabilities and <10 2 current ON/OFF ratios [15], [16].…”

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confidence: 99%

1.2-kV Vertical GaN Fin-JFETs: High-Temperature Characteristics and Avalanche Capability

Liu

Xiao

Zhang

et al. 2021

IEEE Trans. Electron Devices

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This work describes the high-temperature performance and avalanche capability of normally-OFF 1.2-kV-class vertical gallium nitride (GaN) fin-channel junction field-effect transistors (Fin-JFETs). The GaN Fin-JFETs were fabricated by NexGen Power Systems, Inc. on 100-mm GaN-on-GaN wafers. The threshold voltage (V TH) is over 2 V with less than 0.15 V shift from 25 • C to 200 • C. The specific ON-resistance (R ON) increases from 0.82 at 25 • C to 1.8 m•cm 2 at 200 • C. The thermal stability of V TH and R ON are superior to the values reported in SiC MOSFETs and JFETs. At 200 • C, the gate leakage and drain leakage currents remain below 100 μA at −7-V gate bias and 1200-V drain bias, respectively. The gate leakage current mechanism is consistent with carrier hopping across the lateral p-n junction. The high-bias drain leakage current can be well described by the Poole-Frenkel (PF) emission model. An avalanche breakdown voltage (BV AVA) with positive temperature coefficient is shown in both the quasistatic I-V sweep and the unclamped inductive switching (UIS) tests. The UIS tests also reveal a BV AVA over 1700 V and a critical avalanche energy (E AVA) of 7.44 J/cm 2 , with the E AVA comparable to that of state-of-the-art SiC MOSFETs. These results show the great potentials of vertical GaN Fin-JFETs for medium-voltage power electronics applications.

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GaN Vertical-Channel Junction Field-Effect Transistors With Regrown p-GaN by MOCVD

Cited by 31 publications

References 40 publications

Selective Area Regrowth Produces Nonuniform Mg Doping Profiles in Nonplanar GaN p–n Junctions

Selective Area Regrowth Produces Nonuniform Mg Doping Profiles in Nonplanar GaN p–n Junctions

Etched-And-Regrown GaN P–N Diodes with Low-Defect Interfaces Prepared by In Situ TBCl Etching

1.2-kV Vertical GaN Fin-JFETs: High-Temperature Characteristics and Avalanche Capability

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