Optical conductivity tuning and electrical properties of a-Be x Zn y O thin films

Khoshman, Jebreel M.; Jakkala, Pratheesh; Ingram, David C.; Kordesch, Martin E.

doi:10.1016/j.jnoncrysol.2016.03.005

Cited by 15 publications

(6 citation statements)

References 31 publications

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“…This is consistent with the observations of Ritala where crystallites with a preferential orientation in the [100] direction was observed for ALD HfO 2 films. 181 However, we note that a more random orientation has been reported by others for thinner films 56,60 and a [111] orientation has been reported by Berdova for ALD HfO 2 films annealed at 700−900 • C. 251 Thus, while the measured CTE values can be reasonably explained by literature precedent, the grain orientation (or lack of orientation) in ALD HfO 2 films is likely highly dependent on the film thickness and specific growth conditions. This of course neglects the possible presence of anisotropy in the Young's modulus of the ALD HfO 2 film.…”

Section: Methodssupporting

confidence: 72%

Section: 290supporting

confidence: 72%

“…104 More recently, BeO has shown great promise as a barrier layer and gate dielectric in both Si CMOS and III-V high-power and highfrequency device applications, [105][106][107][108][109] and as an alloying agent and oxygen diffusion barrier for ZnO-based optoelectronic devices. [110][111][112] As we will show, ALD BeO exhibits several compelling properties which may make it useful in many additional high-performance applications where extremes in material properties are required.…”

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Review—Investigation and Review of the Thermal, Mechanical, Electrical, Optical, and Structural Properties of Atomic Layer Deposited High-kDielectrics: Beryllium Oxide, Aluminum Oxide, Hafnium Oxide, and Aluminum Nitride

Gaskins

Hopkins

Merrill

et al. 2017

ECS J. Solid State Sci. Technol.

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Atomic layer deposited (ALD) high-dielectric-constant (high-k) materials have found extensive applications in a variety of electronic, optical, optoelectronic, and photovoltaic devices. While electrical, optical, and interfacial properties have been the primary consideration for such devices, thermal and mechanical properties are becoming an additional key consideration for many new and emerging applications of ALD high-k materials in electromechanical, energy storage, and organic light emitting diode devices. Unfortunately, a clear correspondence between thermal/mechanical and electrical/optical properties in ALD high-k materials has yet to be established, and a detailed comparison to conventional silicon-based dielectrics to facilitate optimal material selection is also lacking. In this regard, we have conducted a comprehensive investigation and review of the thermal, mechanical, electrical, optical, and structural properties for a series of prevalent and emerging ALD high-k materials including aluminum oxide (Al 2 O 3 ), aluminum nitride (AlN), hafnium oxide (HfO 2 ), and beryllium oxide (BeO). For comparison, more established silicon-based dielectrics were also examined, including thermally grown silicon dioxide (SiO 2 ) and plasma-enhanced chemically vapor deposited hydrogenated silicon nitride (SiN:H). We find that in addition to exhibiting high values of dielectric permittivity and electrical resistance that exceed those of SiO 2 and SiN:H, the ALD high-k materials exhibit equally exceptional thermal and mechanical properties with coefficients of thermal expansion ≤ 6 × 10 -6 / • C, thermal conductivites (κ) of 3-15 W/m K, and Young's modulus and hardness values exceeding 200 and 25 GPa, respectively. In many cases, the observed extreme thermal/mechanical properties correlate with the presence of crystallinity in the ALD high-k films. In contrast, some of the electrical and optical properties correlate more strongly with the percentage of ionic vs. covalent bonds present in the high-k film. Overall, the ALD high-k dielectrics investigated concurrently exhibit compelling thermal/mechanical and electrical/optical properties. The drive to reduce gate leakage currents in highly scaled complementary metal-oxide-semiconductor (CMOS) transistors has led to the exploration and development of a wide variety of high-dielectricconstant (high-k) materials to replace silicon dioxide (SiO 2 ) as the insulating gate dielectric material.1-8 Many of these same high-k materials have found additional applications in future non-CMOS logic and memory storage products such as solid-state electrolytes in resistive switching devices, 9,10 tunnel barriers in spin-transport devices, 11 and as a ferroelectric in magnetoelectric devices. While electrical, physical, and thermodynamic properties have clearly been a key consideration in all of the above applications, thermal properties have become an additional important consideration for higk-k dielectrics as aggressive dimensional scaling of devices has created the need to dissipate ...

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Section: Methodssupporting

confidence: 72%

Section: 290supporting

confidence: 72%

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confidence: 91%

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Review—Investigation and Review of the Thermal, Mechanical, Electrical, Optical, and Structural Properties of Atomic Layer Deposited High-kDielectrics: Beryllium Oxide, Aluminum Oxide, Hafnium Oxide, and Aluminum Nitride

Gaskins

Hopkins

Merrill

et al. 2017

ECS J. Solid State Sci. Technol.

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“…59 Fig . 7 demonstrates that optical conductivity rises to the highest value of about 1.4 × 10 7 Ω -1 cm -1 with 25 sccm N 2 .…”

Section: -7mentioning

confidence: 99%

Acceptor-modulated optical enhancements and band-gap narrowing in ZnO thin films

et al. 2018

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Fermi-Dirac distribution for doped semiconductors and Burstein-Moss effect have been correlated first time to figure out the conductivity type of ZnO. Hall Effect in the Van der Pauw configuration has been applied to reconcile our theoretical estimations which evince our assumption. Band-gap narrowing has been found in all p-type samples, whereas blue Burstein-Moss shift has been recorded in the n-type films. Atomic Force Microscopic (AFM) analysis shows that both p-type and n-type films have almost same granular-like structure with minor change in average grain size (∼ 6 nm to 10 nm) and surface roughness rms value 3 nm for thickness ∼315 nm which points that grain size and surface roughness did not play any significant role in order to modulate the conductivity type of ZnO. X-ray diffraction (XRD), Energy Dispersive X-ray Spectroscopy (EDS) and X-ray Photoelectron Spectroscopy (XPS) have been employed to perform the structural, chemical and elemental analysis. Hexagonal wurtzite structure has been observed in all samples. The introduction of nitrogen reduces the crystallinity of host lattice. 97% transmittance in the visible range with 1.4 × 107 Ω-1cm-1 optical conductivity have been detected. High absorption value in the ultra-violet (UV) region reveals that NZOs thin films can be used to fabricate next-generation high-performance UV detectors.

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“…Owing to a large bandgap (E g > 8 eV (1,2)), wurtzite crystal structure (3,4), and high solid solubility (5), beryllium oxide (BeO) has recently become of significant interest as an alloying agent with wide bandgap semiconductor zinc oxide (ZnO, E g = 3.3 eV) for bandgap engineering and charge carrier confinement in various oxide semiconductor based optoelectronic devices (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16). BeO also exhibits many other excellent properties (1,(17)(18)(19)(20)(21) including a high dielectric constant (k = 6.7), high breakdown field (E bd > 6 MV/cm), high thermal conductivity (κ > 15 W/mK), and high hardness (H > 30 GPa) that makes it an excellent choice as an insulating gate dielectric (22,23), passivation layer (24,25), diffusion barrier (24), or epitaxial seed layer (27)(28)(29)(30) for both narrow (23,31) and wide bandgap semiconductor devices (32)(33)(34)(35)(36).…”

Section: Introductionmentioning

confidence: 99%

X-Ray Photoemission Investigation of the Beryllium Oxide Band Alignment with Magnesium Oxide and Estimates for Other Insulating and Conducting Oxides

Koh

Hudnall²,

Bielawski

et al. 2021

ECS Trans.

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Beryllium oxide (BeO) is a wurtzite structured, large bandgap (E g > 8 eV) material of significant interest as an alloying agent and cladding dielectric in various oxide based optoelectronic devices. The success of such devices is highly reliant on bandgap and band alignment engineering to achieve sufficient charge carrier and optical confinement for device operation. In this regard, we have utilized x-ray photoemission spectroscopy (XPS) to determine the valence band offset (VBO) between atomic layer deposited (ALD) BeO and a (001) oriented magnesium oxide (MgO) substrate. The BeO VBO with MgO (001) was determined to be 0.1 ± 0.15 eV. Applying the rules of commutativity and transitivity for band alignment, we additionally predict the BeO VBO with other conductive oxides such as ZnO, Ga2O3, and InGaZnO4, to be 1.15 ± 0.3 eV, 0.3 ± 0.2 eV, and 0.9 ± 0.2 eV, respectively.

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Optical conductivity tuning and electrical properties of a-Be x Zn y O thin films

Cited by 15 publications

References 31 publications

Review—Investigation and Review of the Thermal, Mechanical, Electrical, Optical, and Structural Properties of Atomic Layer Deposited High-kDielectrics: Beryllium Oxide, Aluminum Oxide, Hafnium Oxide, and Aluminum Nitride

Review—Investigation and Review of the Thermal, Mechanical, Electrical, Optical, and Structural Properties of Atomic Layer Deposited High-kDielectrics: Beryllium Oxide, Aluminum Oxide, Hafnium Oxide, and Aluminum Nitride

Acceptor-modulated optical enhancements and band-gap narrowing in ZnO thin films

X-Ray Photoemission Investigation of the Beryllium Oxide Band Alignment with Magnesium Oxide and Estimates for Other Insulating and Conducting Oxides

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