H-Terminated Polycrystalline Diamond p-Channel Transistors on GaN-on-Silicon

Soleimanzadeh, Reza; Naamoun, Mehdi; Khadar, Riyaz Abdul; Erp, Remco van; Matioli, Elison

doi:10.1109/led.2019.2953245

Cited by 15 publications

(7 citation statements)

References 25 publications

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“…The maximum sheet carrier concentration we have achieved on a similar PC diamond in our experiments is 6.78 × 10 13 cm −2 with a mobility of 1.42 cm 2 /V•s. The measured characteristics for 2DHG are comparable to the numbers reported for the PC diamond on AlGaN/GaN substrate so far, 27 except that our diamond layer was much thinner (∼1 μm) with a smaller grain size (∼600 nm). A thinner diamond is preferred for integration on top of heterostructures like AlGaN/GaN HEMTs to avoid building enormous residual stress on the interface.…”

Section: Methodssupporting

confidence: 84%

“…In a separate study, the role of PC diamond as a heat spreader was also discussed, making this combination even more desirable for various applications . Unlike the SC diamond, the PC diamond can be directly grown on III-nitride semiconductors, enabling a pathway for monolithic integration of diamond hole FET and GaN HEMT on a single substrate, which forms the foundation of this study. The PC diamond was grown on GaN HEMT using the microwave plasma chemical vapor deposition (MPCVD) technique.…”

Section: Introductionmentioning

confidence: 99%

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Demonstration of Monolithic Polycrystalline Diamond-GaN Complementary FET Technology for High-Temperature Applications

Ren

Malakoutian

et al. 2021

ACS Appl. Electron. Mater.

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We report the first demonstration of a high-temperature-tolerant complementary field-effect transistor (FET) inverter using a monolithic integration of n-channel gallium nitride (GaN) and p-channel diamond. The operation of the inverter up to 250 °C was recorded. A key feature of this work originates from the successful epitaxial growth of p-channel hydrogen-terminated polycrystalline diamond FET on an AlGaN/GaN high-electron-mobility-transistor structure, which then could be coprocessed to realize the inverter. The device stability in the diamond FET was achieved with a ∼45 nm-thick atomic layer deposition of Al2O3 at 450 °C, serving as the gate dielectric as well as passivation for both diamond and GaN transistors. The process window of the coprocessing diamond and AlGaN/GaN was explored extensively to current match the two FETs.

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Section: Methodssupporting

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Demonstration of Monolithic Polycrystalline Diamond-GaN Complementary FET Technology for High-Temperature Applications

Ren

Malakoutian

et al. 2021

ACS Appl. Electron. Mater.

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“…Our measured TBR which was significantly low due to the atomically smooth interface allows phonon transport from the hot spot in the GaN channel to the diamond layer with minimum possible scattering and discontinuity in the temperature profile. The TC of the 2 μm-thick diamond with about the same grain size was measured to be 638 ± 48 W/m K, which is among the highest reported TC for diamond on GaN 12,13 in literature studies and close to the theoretical TC for diamonds with a ∼2 μm grain size. 23 Decreasing the diamond/Si 3 N 4 /GaN TBR from 6.5 m 2 K/GW 27−29 to 3.1 m 2 K/GW and increasing the diamond thickness from 1 to 2 μm for higher TC at the same time reduce the overall channel thermal resistance to ∼6.2 m 2 K/GW.…”

Section: Resultsmentioning

confidence: 98%

“…9−11 Excellent research studies have been reported on integrating diamond and GaN for thermal management. 12,13 In one of the approaches, the substrate is bonded with SC diamond, while in another, chemical vapor-deposited (CVD) PC diamond is grown on the backside of the substrate. 14,15 In contrast to the backside diamond integration, we have presented our approach of integrating PC diamond on top of the device channel by direct CVD growth.…”

Section: Introductionmentioning

confidence: 99%

Record-Low Thermal Boundary Resistance between Diamond and GaN-on-SiC for Enabling Radiofrequency Device Cooling

Malakoutian

Field

Hines

et al. 2021

ACS Appl. Mater. Interfaces

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The implementation of 5G-and-beyond networks requires faster, high-performance, and power-efficient semiconductor devices, which are only possible with materials that can support higher frequencies. Gallium nitride (GaN) power amplifiers are essential for 5G-and-beyond technologies since they provide the desired combination of high frequency and high power. These applications along with terrestrial hub and backhaul communications at high power output can present severe heat removal challenges. The cooling of GaN devices with diamond as the heat spreader has gained significant momentum since device self-heating limits GaN’s performance. However, one of the significant challenges in integrating polycrystalline diamond on GaN devices is maintaining the device performance while achieving a low diamond/GaN channel thermal boundary resistance. In this study, we achieved a record-low thermal boundary resistance of around 3.1 ± 0.7 m2 K/GW at the diamond/Si3N4/GaN interface, which is the closest to theoretical prediction to date. The diamond was integrated within ∼1 nm of the GaN channel layer without degrading the channel’s electrical behavior. Furthermore, we successfully minimized the residual stress in the diamond layer, enabling more isotropic polycrystalline diamond growth on GaN with thicknesses >2 μm and a ∼1.9 μm lateral grain size. More isotropic grains can spread the heat in both vertical and lateral directions efficiently. Using transient thermoreflectance, the thermal conductivity of the grains was measured to be 638 ± 48 W/m K, which when combined with the record-low thermal boundary resistance makes it a leading-edge achievement.

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“…2 A lower cost approach has been proposed by integrating diamond on the cost-effective GaN-on-Si substrates, on which diamond transistors were demonstrated on AlGaN/GaN-on-Si substrates with excellent device characteristics, even without polishing of the rough diamond surfaces. 18 However, the high roughness of as-grown diamond imposes limitations for the wafer processing using planar fabrication methods. Therefore, polishing is an essential step to obtain smooth diamond surfaces and reliable fabrication processes.…”

Section: ■ Introductionmentioning

confidence: 99%

Seed Dibbling Method for the Growth of High-Quality Diamond on GaN

Soleimanzadeh

Naamoun

Floriduz

et al. 2021

ACS Appl. Mater. Interfaces

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The integration of diamond and GaN has been highly pursued for thermal management purposes as well as combining their exceptional complementary properties for power electronics applications and novel semiconductor heterostructures. However, the growth of diamond-on-GaN is challenging due to the high lattice and thermal expansion mismatches. The weak adhesion of diamond to GaN and high residual stresses after the deposition often result in the diamond film delamination or development of cracks, which hinder the subsequent device fabrication. Here, we present a new seed dibbling method for seeding and growing highquality diamond films on foreign substrates, in particular on costeffective GaN-on-Si, with significantly improved adhesion. Diamond films grown conformally on patterned GaN-on-Si presented high quality with significantly larger grains and a 95% sp 3 /sp 2 ratio, excellent interface between diamond and GaN, and lower residual stresses (as low as 0.2 GPa) compared to conventional methods. In addition, the method provided excellent adhesion, enabling a reliable polishing of the as-grown diamond films on GaN on Si without any delamination, resulting in smooth diamond-on-GaN substrates with subnanometer root-mean-square roughness. Diamond layers deposited via seed dibbling resulted in a 2-fold improvement in the effective thermal conductivity for GaN-on-Si with only a 20 μm thick diamond layer. This method opens many new possibilities for the development of high-performance power electronic devices and integrated devices with excellent thermal management based on a diamond-on-GaN platform. In addition, this technique could be extended to other substrates to combine the outstanding properties of diamond with other kinds of devices.

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H-Terminated Polycrystalline Diamond p-Channel Transistors on GaN-on-Silicon

Cited by 15 publications

References 25 publications

Demonstration of Monolithic Polycrystalline Diamond-GaN Complementary FET Technology for High-Temperature Applications

Demonstration of Monolithic Polycrystalline Diamond-GaN Complementary FET Technology for High-Temperature Applications

Record-Low Thermal Boundary Resistance between Diamond and GaN-on-SiC for Enabling Radiofrequency Device Cooling

Seed Dibbling Method for the Growth of High-Quality Diamond on GaN

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