Permittivity increase of yttrium-doped HfO2 through structural phase transformation

Kita, Koji; Kyuno, Kentaro; Toriumi, Akira

doi:10.1063/1.1880436

Cited by 185 publications

(130 citation statements)

References 7 publications

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“…The large energy difference implies that c-BeO would be difficult to stabilize under ambient conditions. However, we pay attention to the experiments in Adelmann et al 25 , Kita et al 26 and Tsipas et al 27 , which indicate that the high-temperature phases of HfO 2 and ZrO 2 can be synthesized as thin films by external doping or strain. More importantly, the doped phases possessed increased dielectric constants, as predicted by theory.…”

Section: Total Property Mapmentioning

confidence: 99%

Novel high-κ dielectrics for next-generation electronic devices screened by automated ab initio calculations

et al. 2015

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As the scale of transistors and capacitors in electronics is reduced to less than a few nanometers, leakage currents pose a serious problem to the device's reliability. To overcome this dilemma, high-κ materials that exhibit a larger permittivity and band gap are introduced as gate dielectrics to enhance both the capacitance and block leakage simultaneously. Currently, HfO 2 is widely used as a high-κ dielectric; however, a higher-κ material remains desired for further enhancement. To find new high-κ materials, we conduct a high-throughput ab initio calculation for band gap and permittivity. The accurate and efficient calculation is enabled by newly developed automation codes that fully automate a series of delicate methods in a highly optimized manner. We can, thus, calculate 41800 structures of binary and ternary oxides from the Inorganic Crystal Structure Database and obtain a total property map. We confirm that the inverse correlation relationship between the band gap and permittivity is roughly valid for most oxides. However, new candidate materials exhibit interesting properties, such as large permittivity, despite their large band gaps. Analyzing these materials, we discuss the origin of large κ values and suggest design rules to find new high-κ materials that have not yet been discovered.

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Section: Total Property Mapmentioning

confidence: 99%

Novel high-κ dielectrics for next-generation electronic devices screened by automated ab initio calculations

et al. 2015

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“…Tetragonal and cubic high temperature phases on the other hand show much higher permittivities (k $ 70 and 29 respectively [4]). These phases have been shown to be stabilized by doping HfO 2 with lanthanides [5][6][7][8]. Besides Hf based materials, lanthanide scandates are reported to be promising as high-k dielectrics, due to their high permittivity (>20) and crystallization resistance up to high temperatures, which is explained by silicate formation [6,9,10].…”

Section: Introductionmentioning

confidence: 99%

Study of interfacial reactions and phase stabilization of mixed Sc, Dy, Hf high-k oxides by attenuated total reflectance infrared spectroscopy

Hardy

Adelmann

Elshocht

et al. 2009

Applied Surface Science

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“…5 In film form, HfO 2 can be deposited by a variety of techniques, including atomic layer deposition, 6 electron beam evaporation, 7 radio frequency, [8][9][10][11][12] direct current, [13][14][15] pulsed 16 and high pressure 17 magnetron sputtering, molecular beam epitaxy, 18 and pulse laser deposition. 2,3 With all these techniques, growth at room temperature commonly results in the formation of the m-HfO 2 phase 10,12,16,17,19,20 or amorphous films. 2,3,[5][6][7][8]13,15 Therefore, considerable research effort has been focused on the room temperature growth of the t-and the c-HfO 2 phases.…”

Section: Introductionmentioning

confidence: 99%

On the phase formation of sputtered hafnium oxide and oxynitride films

Sarakinos

Mušić

Mráz

et al. 2010

Journal of Applied Physics

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Hafnium oxynitride films are deposited from a Hf target employing direct current magnetron sputtering in an Ar-O 2 -N 2 atmosphere. It is shown that the presence of N 2 allows for the stabilization of the transition zone between the metallic and the compound sputtering mode enabling deposition of films at well defined conditions of target coverage by varying the O 2 partial pressure. Plasma analysis reveals that this experimental strategy facilitates control over the flux of the O − ions which are generated on the oxidized target surface and accelerated by the negative target potential toward the growing film. An arrangement that enables film growth without O − ion bombardment is also implemented. Moreover, stabilization of the transition sputtering zone and control of the O − ion flux without N 2 addition is achieved employing high power pulsed magnetron sputtering. Structural characterization of the deposited films unambiguously proves that the phase formation of hafnium oxide and hafnium oxynitride films with the crystal structure of HfO 2 is independent from the O − bombardment conditions. Experimental and theoretical data indicate that the presence of vacancies and/or the substitution of O by N atoms in the nonmetal sublattice favor the formation of the cubic and/or the tetragonal HfO 2 crystal structure at the expense of the monoclinic HfO 2 one.

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Permittivity increase of yttrium-doped HfO2 through structural phase transformation

Cited by 185 publications

References 7 publications

Novel high-κ dielectrics for next-generation electronic devices screened by automated ab initio calculations

Novel high-κ dielectrics for next-generation electronic devices screened by automated ab initio calculations

Study of interfacial reactions and phase stabilization of mixed Sc, Dy, Hf high-k oxides by attenuated total reflectance infrared spectroscopy

On the phase formation of sputtered hafnium oxide and oxynitride films

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