Emerging Applications for High K Materials in VLSI Technology

Clark, Robert D.

doi:10.3390/ma7042913

Cited by 144 publications

(84 citation statements)

References 161 publications

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“…125,126 We do note that the above mentioned film thicknesses are significantly higher than those typically utilized in traditional Si CMOS high-k dielectric applications where thicknesses of <10 nm are more common. [2][3][4][5][6][7][8] However, many of the applications involving these materials as diffusion barriers, 27,31,127 nano-resonators, 80,81 and piezoelectric transducers 43,87 can require significantly higher thicknesses of 20-1000 nm. Also, use of film thicknesses >100 nm minimize substrate 128 and interfacial thermal boundary resistance 129 effects that can complicate the mechanical and thermal property measurements, respectively.…”

Section: Methodsmentioning

confidence: 99%

“…44,45 For such devices, knowledge of properties such as Young's modulus and film stress are critical for predicting the flexure and resonance frequencies of bridged and cantilevered switches and sensors, [46][47][48][49] stretched transistor device performance, 50,51 buckling failures in nanopatterned structures, 52,53 and macroscale buckling and nanoscale wrinkling effects for stiff high-k films deposited on compliant polymeric substrates. 54,55 Unfortunately, only a limited number of studies have reported on the thermal [56][57][58][59] and mechanical 42,[60][61][62][63][64][65][66] properties of ALD highk dielectric materials, and the numerous reviews [2][3][4][5][6][7][8] of high-k dielectrics have focused primarily on the electronic structure and interfacial properties of high-k dielectrics from a CMOS device perspective. To the authors' knowledge, a clear correspondence between thermal/mechanical and electrical/optical properties for ALD high-k dielectrics has yet to be established.…”

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confidence: 99%

“…[1][2][3][4][5][6][7][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. 12,13 They have also enabled significant performance gains in a wide variety of energy storage, 14,15 photovoltaic, 16,17 optoelectronic, 18 high-frequency, 19,20 high-power, 21 and high-temperature devices.…”

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confidence: 99%

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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: Methodsmentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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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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“…4,5 For superior device performance at sub 10 nm nodes, germanium is being considered as an alternate channel material, owing to its intrinsic high mobility (electrons: 3900 cm 2 V À1 s…”

Section: Introductionmentioning

confidence: 99%

Role of Ge and Si substrates in higher-k tetragonal phase formation and interfacial properties in cyclical atomic layer deposition-anneal Hf1−xZrxO2/Al2O3 thin film stacks

Dey

Tapily²,

Consiglio³

et al. 2016

Journal of Applied Physics

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Using a five-step atomic layer deposition (ALD)-anneal (DADA) process, with 20 ALD cycles of metalorganic precursors followed by 40 s of rapid thermal annealing at 1073 K, we have developed highly crystalline Hf 1Àx Zr x O 2 (0 x 1) thin films (<7 nm) on $1 nm ALD Al 2 O 3 passivated Ge and Si substrates for applications in higher-k dielectric metal oxide semiconductor field effect transistors below 10 nm technology node. By applying synchrotron grazing incidence x-ray d-spacing maps, x-ray photoelectron spectroscopy (XPS), and angle-resolved XPS, we have identified a monoclinic to tetragonal phase transition with increasing ZrO 2 content, elucidated the role of the Ge vs Si substrates in complete tetragonal phase formation (CTPF), and determined the interfacial characteristics of these technologically relevant films. The ZrO 2 concentration required for CTPF is lower on Ge than on Si substrates (x $ 0.5 vs. x $ 0.86), which we attribute as arising from the growth of an ultra-thin layer of metal germanates between the Hf 1Àx Zr x O 2 and Al 2 O 3 /Ge, possibly during the first deposition and annealing cycle. Due to Ge-induced tetragonal phase stabilization, the interfacial metal germanates could act as a template for the subsequent preferential growth of the tetragonal Hf 1Àx Zr x O 2 phase following bottom-up crystallization during the DADA ALD process. We surmise that the interfacial metal germanate layer also function as a diffusion barrier limiting excessive Ge uptake into the dielectric film. An ALD Al 2 O 3 passivation layer of thickness !1.5 nm is required to minimize Ge diffusion for developing highly conformal and textured HfO 2 based higher-k dielectrics on Ge substrates using the DADA ALD process. Published by AIP Publishing.

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“…Hafnium (Hf)-based compounds such as HfO 2 , Hf-silicate, and nitride Hf-silicate have been intensively studied as candidate materials to replace SiO 2 in advanced metal-insulator-semiconductor field-effect transistors (MISFETs). [1][2][3][4][5][6][7] Hf-silicate is a most promising material because of its relatively high dielectric constant when compared with that of SiO 2 (ε r = 10−20, depending on Hf content 8 ), wide band gap (E g ∼6 eV), large (1.5 eV) conduction band offset to Si, 9 and low interface state density with Si (D it = 1-6×10 11 cm 2 eV 1 ). 4 Another highly attractive feature of Hf-silicate is its thermodynamic stability when directly deposited on Si substrates.…”

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confidence: 99%

Room temperature formation of Hf-silicate layer by pulsed laser deposition with Hf-Si-O ternary reaction control

et al. 2016

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Emerging Applications for High K Materials in VLSI Technology

Cited by 144 publications

References 161 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

Role of Ge and Si substrates in higher-k tetragonal phase formation and interfacial properties in cyclical atomic layer deposition-anneal Hf1−xZrxO2/Al2O3 thin film stacks

Room temperature formation of Hf-silicate layer by pulsed laser deposition with Hf-Si-O ternary reaction control

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