Activating Thick Buried p-GaN for Device Applications

Ma, Yunwei; Xiao, Ming; Du, Zhonghao; Wang, Lei; Carlson, E.P.; Guido, L. J.; Wang, Han; Wang, Lai; Luo, Yi; Zhang, Yuhao

doi:10.1109/ted.2022.3186652

Cited by 6 publications

(3 citation statements)

References 45 publications

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“…It was found that the high carbon-doped concentration (high carbon) 10 19 cm −3 has 171 V higher breakdown voltage than (low carbon) 10 18 cm −3 at 1 A cm −2 , Table 1. Carrier transport mechanisms [9][10][11][12][13][14][15][16][17][18].…”

Section: Resultsmentioning

confidence: 99%

“…Here, we consider that carbon would replace N or Ga, possibly acting as acceptor or donor [6][7][8]. At present, there are several leakage mechanisms on GaN-based epitaxial layers as shown in table 1 [9][10][11][12][13][14][15][16][17][18]. Among them, Zhou et al [9] have used accepted and donored ionization to analyze doped GaN high-electron-mobility transistors (HEMTS) leakage mechanism, and found space-charge-limited current (SCLC) models [9,10] make a key role.…”

Section: Introductionmentioning

confidence: 99%

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The role of point defects related with carbon impurity on the kink of log J–V in GaN-on-Si epitaxial layers

Song¹,

Liu²,

Yang³

et al. 2022

Nanotechnology

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Carbon impurity as point defects makes key impact on the leakage in GaN-on-Si structures. GaN-based epitaxial layers with different point defects by changing carbon-doped concentration were used to investigate the point defects behavior. It was found that leakage mechanisms correspond with space-charge-limited current models at low voltages, and after 1st kink, electron injection from silicon to GaN and PF conduction play a key role in the leakage of both point defects case with low carbon and high carbon doped. In addition, high carbon in GaN-on-Si epitaxial layers obtained lower leakage and larger breakdown voltage. The slope of log J-V has two kinks and effective energy barrier Ea has two peaks, 0.4247eV at about 300V and 0.3485eV at about 900V, respectively, which is related to accepted states and donor states related with carbon impurity. While the slope of log J-V has one kink and effective energy barrier Ea has one peak, 0.4794eV at about 400V of low carbon in GaN-on-Si epitaxial layers, indicating only Field-induced accepted ionized makes impact on leakage. The comparative results of more donor trap density in high carbon indicate point defects related with carbon impurity play a key role in the kinks of log J-V slope.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The role of point defects related with carbon impurity on the kink of log J–V in GaN-on-Si epitaxial layers

Song¹,

Liu²,

Yang³

et al. 2022

Nanotechnology

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“…The first involves growing a buried p-GaN layer beneath the n-GaN, which forms a PN junction and prevents the flow of leakage current. While this approach is effective, it requires activation of the buried p-GaN layer after the isolation etch so that Mg passivating hydrogen can diffuse out through the etch sidewalls [21][22][23][24] . Mg activation becomes less effective as device dimensions increase, due to increased out-diffusion path lengths of hydrogen.…”

Section: Introductionmentioning

confidence: 99%

Photoresist planarized trench isolation for monolithic GaN µLED displays

Melanson

Seitz

Zhang

2023

Gallium Nitride Materials and Devices XVIII

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Micro-Light-Emitting Diode (µLED) displays have seen increasing interest over the past decade due to their promising advantages over other display technologies, especially in applications requiring extremely high resolutions such as virtual and alternate reality headsets. Most modern full-color µLED displays rely on red, green, and blue (RGB) pixels based on different material systems combined together on a thin-film transistor back panel, which is often costly and has poor yield. An alternative approach is to create a monolithic display in the GaN/InGaN material system, capable of covering the entire visible spectrum through tuning of quantum well (QW) Indium content or phosphor down conversion. However, monolithic GaN displays present the issue of pixel isolation, as the lack of truly insulating undoped GaN (u-GaN) makes it difficult to electrically isolate rows or columns of µLEDs from one another.In this work, we demonstrate a novel solution to this issue which utilizes photoresist to fill deep trench isolation features, enabling interconnection of µLED p-contacts in a single-color passive matrix display. A photoresist layer is used to fill deep trenches isolating columns of µLEDs from one another. This photoresist layer is patterned and baked at 250 °C for 30 minutes, crosslinking it and making it extremely durable. This process allows for formation of p-interconnects using liftoff, and avoids the issues involved in bridging high aspect ratio trenches. This photoresist planarized trench isolation process could contribute to creation of improved monolithic full color µLED displays which require multiple deep isolation features to be bridged by conductive interconnects.

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