Compton profile study of bonding in BeO

Joshi, K. B.; Jain, Rajesh; Pandya, R.; Ahuja, B.L.; Sharma, B. K.

doi:10.1063/1.479262

Cited by 53 publications

(17 citation statements)

References 22 publications

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“…Since the high-frequency dielectric constant represents only electronic contributions to dielectric permittivity and the low-frequency dielectric constant includes electronic, ionic, and configurational contributions, 193 the higher low-frequency dielectric constant for HfO 2 points toward essentially complete ionic bonding and possibly some configurational contributions. 4 This is consistent with the significant covalent bonding character reported for BeO, AlN, 194,195 and, to a lesser degree, Al 2 O 3 .…”

supporting

confidence: 87%

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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supporting

confidence: 87%

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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“…Figure depicts that the EVED profile corresponding to AlAs is larger around the low momentum region compared to AlN. As the larger value around low momentum is attributed to larger covalent character [32], it points that AlAs is more covalent and less ionic than AlN in agreement with earlier studies [33,34]. The larger anisotropies in AlAs compared to the AlN also confirm these findings.…”

Section: Equal Valence Electron Density Profilessupporting

confidence: 87%

Electronic structure of AlAs: A Compton profile study

Sharma

Joshi

Mishra

et al. 2009

Journal of Alloys and Compounds

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“…It might be due to difference in bonding characteristics of WS 2 and WSe 2 . It is established that covalent bonding is a result of overlap of wave functions in the direction of bonding, it increases localisation of charge along the bond direction leading to sharper Compton line shape [38]. Thus the sharper line shape seen in the EVED plot of WSe 2 can be attributed to more covalent bonding character of WSe 2 as compared to WS 2 .…”

Section: Eved Profilesmentioning

confidence: 93%