Structure and Interface Analysis of Diamond on an AlGaN/GaN HEMT Utilizing an in Situ SiN<i>x</i> Interlayer Grown by MOCVD

Siddique, Anwar; Ahmed, Raju; Anderson, Jonathan; Nazari, Mohammad; Yates, Luke; Graham, Samuel; Holtz, M.; Piner, Edwin L.

doi:10.1021/acsaelm.9b00131

Cited by 41 publications

(33 citation statements)

References 68 publications

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“…At the same time the bottleneck of the heat extraction was recognized to be the TBR between GaN and diamond (TBR GaN/diamond ) [72] and most of following research focused on decreasing it, whether by decreasing the dielectric thickness, by using a different dielectric, or by optimizing the diamond nucleation layer [10,[72][73][74][75][76][77][78][79][80][81][82][83][84]. The impact of the thickness of the GaN buffer layer on the R th of the HEMT devices [85][86][87][88][89][90] and the effects of the stress caused by the difference in the CTEs of GaN and diamond [91][92][93][94][95][96] were also evaluated by different research groups. A more detailed description and discussion of the main findings is included in Section 4.1.…”

Section: Gan-on-diamondmentioning

confidence: 99%

“…The appearance of biaxial strain in the Al(Ga)N layers due to the high diamond deposition temperatures, the lattice mismatch between the layers, and the different CTEs of the stack materials was studied in detail by Siddique et al [91]. In their study, a 46 nm-thick SiN layer was used to protect the III-nitride layers beneath the AlGaN barrier layer during the diamond CVD.…”

Section: Capping Diamondmentioning

confidence: 99%

“…One of the biggest issues of this approach is related with the high diamond deposition temperature (>700 • C) which induces a large residual stress at the GaN/diamond interface because of the mismatch between the CTEs of both materials [159,160]. The residual stress depends on the GaN thickness, on the diamond growth temperature, and on the sacrificial carrier wafer [91,92]. Residual stresses larger than 1 GPa at the free surface of the GaN have been reported [93]; these elevated stress conditions induce layer cracking and wafer bow, and impact the electrical performance of the devices [161][162][163][164].…”

Section: Decreasing Thermal Stressmentioning

confidence: 99%

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Diamond/GaN HEMTs: Where from and Where to?

Mendes

Liehr²,

Li³

2022

Materials

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Gallium nitride is a wide bandgap semiconductor material with high electric field strength and electron mobility that translate in a tremendous potential for radio-frequency communications and renewable energy generation, amongst other areas. However, due to the particular architecture of GaN high electron mobility transistors, the relatively low thermal conductivity of the material induces the appearance of localized hotspots that degrade the devices performance and compromise their long term reliability. On the search of effective thermal management solutions, the integration of GaN and synthetic diamond with high thermal conductivity and electric breakdown strength shows a tremendous potential. A significant effort has been made in the past few years by both academic and industrial players in the search of a technological process that allows the integration of both materials and the fabrication of high performance and high reliability hybrid devices. Different approaches have been proposed, such as the development of diamond/GaN wafers for further device fabrication or the capping of passivated GaN devices with diamond films. This paper describes in detail the potential and technical challenges of each approach and presents and discusses their advantages and disadvantages.

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Section: Gan-on-diamondmentioning

confidence: 99%

Section: Capping Diamondmentioning

confidence: 99%

Section: Decreasing Thermal Stressmentioning

confidence: 99%

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Diamond/GaN HEMTs: Where from and Where to?

Mendes

Liehr²,

Li³

2022

Materials

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“…[9][10][11][12] The high growth temperature of the diamond also induces large residual stress in the GaN because of the mismatch of the coefficients of thermal expansion. 13,14 Stresses generated during the direct growth of diamond on GaN have been shown to vary, dependent upon GaN thickness, diamond growth temperature, and the sacrificial carrier wafer 15,16 .…”

Section: Introductionmentioning

confidence: 99%

Interfacial Thermal Conductance across Room-Temperature-Bonded GaN/Diamond Interfaces for GaN-on-Diamond Devices

Cheng

Yates

et al. 2020

ACS Appl. Mater. Interfaces

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137

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The wide bandgap, high-breakdown electric field, and high carrier mobility makes GaN an ideal material for high-power and high-frequency electronics applications such as wireless communication and radar systems. However, the performance and reliability of GaN-based high electron mobility transistors (HEMTs) are limited by the high channel temperature induced by Joule-heating in the device channel. High thermal conductivity substrates (e.g., diamond) integrated with GaN can improve the extraction of heat from GaN-based HEMTs and lower the device operating temperature. However, heterogeneous integration of GaN with diamond substrates is not trivial and presents technical challenges to maximize the heat dissipation potential brought by the diamond substrate. In this work, two modified room-temperature surface-activated bonding (SAB) techniques are used to bond GaN and single crystal diamond with different interlayer thicknesses. Time-domain thermoreflectance (TDTR) is used to measure the thermal properties from room temperature to 480 K. A relatively large thermal boundary conductance (TBC) of the GaN-diamond interfaces with a ~4-nm interlayer (~90 MW/m 2 -K) was observed and material characterization was performed to link the structure of the interface to the TBC. Device modeling shows that the measured GaN-diamond TBC values obtained from bonding can enable high power GaN devices by taking the full advantage of the high thermal conductivity of single crystal diamond and achieve excellent cooling effect. Furthermore, the room-temperature bonding process in this work do not induce stress problem due to different coefficient of thermal expansion in other high temperature integration processes in previous studies. Our work sheds light on the potential for room-temperature heterogeneous integration of semiconductors with diamond for applications of electronics cooling especially for GaN-on-diamond devices.

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“…However, heterogeneous integration of GaN with diamond leading to the GaN-on-diamond architecture is still challenging. Up to now, three kinds of approaches to fabricate the GaN-on-diamond architecture have been demonstrated: (i) diamond growth on GaN [13][14][15][16], (ii) GaN growth on diamond [17][18][19], and (iii) GaNdiamond bonding technology [20][21][22][23]. In the first two approaches, a nucleation layer is formed at the initial stage of growth, resulting in a large number of defects and grain boundaries at the interface, which have a negative impact on the thermal performance of the GaN-on-diamond device due to the poor thermal conductivity [5].…”

Section: Introductionmentioning

confidence: 99%

DFT-Based Studies on Carbon Adsorption on the wz-GaN Surfaces and the Influence of Point Defects on the Stability of the Diamond–GaN Interfaces

Sznajder

Hrytsak

2021

Materials

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Integration of diamond with GaN-based high-electron-mobility transistors improves thermal management, influencing the reliability, performance, and lifetime of GaN-based devices. The current GaN-on-diamond integration technology requires precise interface engineering and appropriate interfacial layers. In this respect, we performed first principles calculation on the stability of diamond–GaN interfaces in the framework of density functional theory. Initially, some stable adsorption sites of C atoms were found on the Ga- and N-terminated surfaces that enabled the creation of a flat carbon monolayer. Following this, a model of diamond–GaN heterojunction with the growth direction [111] was constructed based on carbon adsorption results on GaN{0001} surfaces. Finally, we demonstrate the ways of improving the energetic stability of diamond–GaN interfaces by means of certain reconstructions induced by substitutional dopants present in the topmost GaN substrate’s layer.

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Structure and Interface Analysis of Diamond on an AlGaN/GaN HEMT Utilizing an in Situ SiNx Interlayer Grown by MOCVD

Cited by 41 publications

References 68 publications

Diamond/GaN HEMTs: Where from and Where to?

Diamond/GaN HEMTs: Where from and Where to?

Interfacial Thermal Conductance across Room-Temperature-Bonded GaN/Diamond Interfaces for GaN-on-Diamond Devices

DFT-Based Studies on Carbon Adsorption on the wz-GaN Surfaces and the Influence of Point Defects on the Stability of the Diamond–GaN Interfaces

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