Effect of compositionally graded AlGaN buffer layer grown by different functions of trimethylaluminum flow rates on the properties of GaN on Si (111) substrates

Yang, Yibin; Xiang, Peng; Liu, Minggang; Chen, Weijie; He, Zhiyuan; Han, Xiumei; Ni, Yiqiang; Yang, Fan; Yao, Yao; Wu, Zhisheng; Yang, Liting; Zhang, Baijun

doi:10.1016/j.jcrysgro.2013.04.043

Cited by 44 publications

(24 citation statements)

References 37 publications

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“…Unparalleled large-area availability, low-cost, and fabrication maturity make silicon the most commercially attractive among the three. However, along with lattice mismatch, epitaxy of III-nitrides on silicon brings the additional challenges of melt-back etching , and stress management. , This has resulted in AlN nucleation , layers and graded AlGaN buffers , becoming integral components of III-nitride heterostructures grown on silicon. At times, the adverse electrical implications of these additional layers have proven to be a reason for concern, necessitating further scrutiny.…”

Section: Introductionmentioning

confidence: 99%

Origin(s) of Anomalous Substrate Conduction in MOVPE-Grown GaN HEMTs on Highly Resistive Silicon

Ghosh

Hinz

Fairclough

et al. 2021

ACS Appl. Electron. Mater.

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The performance of transistors designed specifically for high-frequency applications is critically reliant upon the semiinsulating electrical properties of the substrate. The suspected formation of a conductive path for radio frequency (RF) signals in the highly resistive (HR) silicon substrate itself has been long held responsible for the suboptimal efficiency of as-grown GaN high electron mobility transistors (HEMTs) at higher operating frequencies. Here, we reveal that not one but two discrete channels distinguishable by their carrier type, spatial extent, and origin within the metal-organic vapor phase epitaxy (MOVPE) growth process participate in such parasitic substrate conduction. An ntype layer that forms first is uniformly distributed in the substrate, and it has a purely thermal origin. Alongside this, a p-type layer is localized on the substrate side of the AlN/Si interface and is induced by diffusion of group-III element of the metal-organic precursor. Fortunately, maintaining the sheet resistance of this p-type layer to high values (∼2000 Ω/□) seems feasible with particular durations of either organometallic precursor or ammonia gas predose of the Si surface, i.e., the intentional introduction of one chemical precursor just before nucleation. It is proposed that the mechanism behind the control actually relies on the formation of disordered AlSiN between the crystalline AlN nucleation layer and the crystalline silicon substrate.

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Section: Introductionmentioning

confidence: 99%

Origin(s) of Anomalous Substrate Conduction in MOVPE-Grown GaN HEMTs on Highly Resistive Silicon

Ghosh

Hinz

Fairclough

et al. 2021

ACS Appl. Electron. Mater.

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“…[5][6][7][8][9] Moreover, there have been further demonstrations that compositionally graded Al x Ga 1Àx N may also serve as strain transition buffer layers and dislocation filters for the growth of crack-free GaN on Si(111) substrates. [10][11][12] The depth profile of the aluminum content is the key factor in modifying the properties of graded Al x Ga 1Àx N layers. Thus, a crucial issue in the growth of these layers is the precise control of the Al flux so that the composition changes controllably with depth.…”

Section: Introductionmentioning

confidence: 99%

Measuring the depth profiles of strain/composition in AlGaN-graded layer by high-resolution x-ray diffraction

Kuchuk

Stanchu

et al. 2014

Journal of Applied Physics

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Here, we demonstrate X-ray fitting through kinematical simulations of the intensity profiles of symmetric reflections for epitaxial compositionally graded layers of AlGaN grown by molecular beam epitaxy pseudomorphically on [0001]-oriented GaN substrates. These detailed simulations depict obvious differences between changes in thickness, maximum concentration, and concentration profile of the graded layers. Through comparison of these simulations with as-grown samples, we can reliably determine these parameters, most important of which are the profiles of the concentration and strain which determine much of the electrical properties of the film. In addition to learning about these parameters for the characterization of thin film properties, these fitting techniques create opportunities to calibrate growth rates and control composition profiles of AlGaN layers with a single growth rather than multiple growths as has been done traditionally.

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“…Threading dislocations propagate vertically along the growth direction and do not decrease much with the growth of the GaN, which is generally observed for the growth of III‐nitrides . Conversely, in the DH, as the Al content of the graded Al x Ga 1– x N gradually changes, the compression stress in the graded Al x Ga 1– x N buffer layer also changes, which induces the threading dislocations to bend, merge, and even annihilate . Therefore, the higher crystalline quality and smooth surface of the DH HEMT on sapphire are obtained.…”

Section: Resultsmentioning

confidence: 93%

Overcoming the poor crystal quality and DC characteristics of AlGaN/GaN/AlGaN double‐heterostructure high electron mobility transistors

Zhang

et al. 2016

Physica Status Solidi (a)

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We report Al0.30Ga0.70N/GaN/Al0.07Ga0.93N double‐heterostructure high electron mobility transistors (DH HEMTs) with admirable DC characteristics fully surpassing those of the Al0.30Ga0.70N/GaN single‐heterostructure (SH) HEMTs. The DH HEMTs feature a 1400‐nm graded AlxGa1–xN (x = 0–0.06) buffer layer, a 300‐nm Al0.07Ga0.93N back barrier layer, and a 70‐nm thick GaN channel layer. Due to the improved cystal quality and enhanced confinement of the carriers, the DH HEMTs presented have shown improved performance with respect to the conventional SH HEMTs, including electron mobility promoted from 1701 to 1744 cm2 V−1 s−1, surface roughness in terms of root mean square values (RMS) reduced from 0.19 to 0.16 nm, (10–12) full widths at half‐maximum (FWHMs) reduced from 726 to 540 arcsec, subthreshold swing (SS) reduced from 113 to 78 mV dec−1, Ion/Ioff ratio increased from 105.3 to 106.2, drain‐induced barrier lowering (DIBL) reduced from 24 and 14 mV V−1, and breakdown voltage promoted from 59 to 109 V.

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Effect of compositionally graded AlGaN buffer layer grown by different functions of trimethylaluminum flow rates on the properties of GaN on Si (111) substrates

Cited by 44 publications

References 37 publications

Origin(s) of Anomalous Substrate Conduction in MOVPE-Grown GaN HEMTs on Highly Resistive Silicon

Origin(s) of Anomalous Substrate Conduction in MOVPE-Grown GaN HEMTs on Highly Resistive Silicon

Measuring the depth profiles of strain/composition in AlGaN-graded layer by high-resolution x-ray diffraction

Overcoming the poor crystal quality and DC characteristics of AlGaN/GaN/AlGaN double‐heterostructure high electron mobility transistors

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