Parameter window of diamond growth on GaN films by microwave plasma chemical vapor deposition

Mohapatra, Dipti Ranjan; Rai, Padmnabh; Misra, Abha; Tyagi, Pawan; Yadav, B. S.; Misra, D.S.

doi:10.1016/j.diamond.2008.02.011

Cited by 7 publications

(2 citation statements)

References 17 publications

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“…For diamond growth, H 2 plasma is necessary to break C–H bonds (of CH 4 gas or the seeded substrate) and provide CH 3 + to the surface for diamond growth. , However, H 2 plasma causes damage to the surface material (GaN) which degrades the properties of the two-dimensional-electron gas (2DEG) as it is very close to the surface in N-polar HEMTs. One conventional approach is to utilize a thin layer of a gate dielectric to protect the GaN channel. ,,− Since most dielectrics (Si 3 N 4 , SiO 2 , and Al 2 O 3 ) have a poor TC (<50 W/m K), the thermal resistance from the channel to the external heat sink increases. Therefore, the dielectric must be as thin as possible (∼5 nm) to dissipate the heat effectively but also needs to be thick enough to protect the underlying GaN from damage.…”

Section: Introductionmentioning

confidence: 99%

Development of Polycrystalline Diamond Compatible with the Latest N-Polar GaN mm-Wave Technology

Malakoutian

Ren

Woo

et al. 2021

Crystal Growth & Design

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Integration of diamond on GaN can ease the challenges associated with thermal management of GaN-based power amplifiers which need to base on highly scaled transistors to push toward higher frequencies at high powers for 5G networks. The integration of diamond was achieved by growing polycrystalline (PC) diamond on nitrogen-polar GaN. A standard 5 nm Si3N4 layer which forms the gate dielectric was used as an interlayer between diamond and the GaN channel for etching protection. Since diamond growth conditions involve high temperature and H2 plasma, it can easily decompose the underlying dielectric as well as the GaN channel and degrade the channel conductivity and hence the device performance. Due to the incompatibility of conventional growth recipes with thin dielectrics (<5 nm), a novel two-stage-three-step growth recipe was designed for PC diamond integration on top of nitrogen-polar GaN high-electron-mobility transistors in a H2/CH4-plasma environment. Using only H2 and CH4 in the chamber guarantees a higher-phase-purity diamond than chambers with added argon or nitrogen for lower substrate etching. This recipe maintains the performance of the two-dimensional-electron gas and provides a less columnar diamond structure with a larger grain size. Our observations were supported by scanning transmission electron microscopy and Hall mobility measurements using the van der Pauw technique before and after diamond growth. A mobility of ∼1250 cm2/V s, a sheet carrier concentration of ∼1.30 × 1013 cm–2, and a sheet resistivity of ∼380 Ω/□ were maintained after the growth of diamond. The anisotropy ratio has been decreased from 3.75 to 1.12 with this growth recipe. Using long channel devices, we measured the difference in the channel temperature, which decreased by more than 100 °C in the range of 10–24 W/mm power after the integration of the diamond on top of the device.

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Section: Introductionmentioning

confidence: 99%

Development of Polycrystalline Diamond Compatible with the Latest N-Polar GaN mm-Wave Technology

Malakoutian

Ren

Woo

et al. 2021

Crystal Growth & Design

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“…There are several prior studies that investigated the seeding of the GaN surface with diamond nanoparticles, which primarily focused on utilizing ultrasonic agitation. In most of the previous reports, a protective layer (Si 3 N 4 or SiO 2 ) is used to prevent GaN etching during the polycrystalline diamond deposition [14][15][16][17][18][19][20]. While ultrasonication is one of the common methods for seeding of GaN substrates in the literature time varies between seconds to hours in a variety of solvents like DI water, ethanol, or methanol.…”

Section: Introductionmentioning

confidence: 99%

A study on the nucleation and MPCVD growth of thin, dense, and contiguous nanocrystalline diamond films on bare and Si₃N₄-coated N-polar GaN

Laurent

Malakoutian

Chowdhury

2019

Semicond. Sci. Technol.

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We report upon the microwave plasma chemical vapor deposition (MPCVD) growth of polycrystalline diamond on varying crystallographic orientations of GaN (Ga-polar and N-polar), as well as on Si 3 N 4 -coated N-polar GaN, as applied to top-side heat spreading layers for III-N-based high electron mobility transistors. Integration of diamond with GaN in this configuration is subject to differing process constraints from previous research focusing on backside heat sinks. A critical requirement is to prevent hydrogen-related etching of the III-N surface in the H + plasma ambient, as well as to avoid plasma damage to the GaN crystal or HEMT channel region near the surface. Thus we developed the seeding and MPCVD techniques under a low power density plasma with low sample temperatures during deposition. We systematically investigated samples seeded via polymer-assisted dip seeding in a nanoparticle suspension, which were then subjected to MPCVD growth under identical conditions. We evaluated the quality of the films via scanning electron microscopy and Raman spectroscopy to understand the relationship between grain size, interface abruptness, propensity for surface etching, as well as film uniformity. Finally, we were able to identify a process window for both N-polar GaN and Si 3 N 4 -coated N-polar GaN which yields thin, fully coalesced, nanocrystalline diamond films with an abrupt interface to the underlying substrate. These diamond films exhibit microscopic uniformity in crystal grain size, and macroscopic uniformity in thickness and interface abruptness via a process which is scalable to large wafer sizes.

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Effect of linear antenna chemical vapor deposition process parameters on the growth of nanocrystalline diamond-on-GaN films

Kumar Mallik,

Pobedinskas,

Krishnamurthy

et al. 2024

Journal of Crystal Growth

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Parameter window of diamond growth on GaN films by microwave plasma chemical vapor deposition

Cited by 7 publications

References 17 publications

Development of Polycrystalline Diamond Compatible with the Latest N-Polar GaN mm-Wave Technology

Development of Polycrystalline Diamond Compatible with the Latest N-Polar GaN mm-Wave Technology

A study on the nucleation and MPCVD growth of thin, dense, and contiguous nanocrystalline diamond films on bare and Si₃N₄-coated N-polar GaN

Effect of linear antenna chemical vapor deposition process parameters on the growth of nanocrystalline diamond-on-GaN films

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Parameter window of diamond growth on GaN films by microwave plasma chemical vapor deposition

Cited by 7 publications

References 17 publications

Development of Polycrystalline Diamond Compatible with the Latest N-Polar GaN mm-Wave Technology

Development of Polycrystalline Diamond Compatible with the Latest N-Polar GaN mm-Wave Technology

A study on the nucleation and MPCVD growth of thin, dense, and contiguous nanocrystalline diamond films on bare and Si3N4-coated N-polar GaN

Effect of linear antenna chemical vapor deposition process parameters on the growth of nanocrystalline diamond-on-GaN films

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A study on the nucleation and MPCVD growth of thin, dense, and contiguous nanocrystalline diamond films on bare and Si₃N₄-coated N-polar GaN