Impact of layer thickness on the ferroelectric behaviour of silicon doped hafnium oxide thin films

Yurchuk, Ekaterina; Müller, Johannes; Knebel, S.; Sundqvist, Jonas; Graham, Andrew; Melde, T.; Schröder, Uwe; Mikolajick, Thomas

doi:10.1016/j.tsf.2012.11.125

Cited by 170 publications

(108 citation statements)

References 26 publications

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“…In this connection, anisotropic stresses are required for the phase transition from tetragonal to orthorhombic, i.e., a compressive stress within the aob plane and a tensile stress along the c-axis exerted on the t-phase. There are many factors reported hitherto to be responsible for causing the anisotropic stresses and thus stabilizing the ferroelectric o-phase during the film growth, such as doping, 4,5,[23][24][25][26][27][28][29][30][31][32][33][34][35] surface energy effect, [36][37][38] island coalescence, 39 thermal expansion mismatch, 17 capping layer effect, 4,38 and formation of oxygen vacancies. 40 The following of this section will discuss each of these factors in order.…”

Section: Origins Of Ferroelectricity In Hfo 2 -Based Materialsmentioning

confidence: 99%

“…By comparing the Helmholtz free energies of various HfO 2 (and Hf 0:5 Zr 0:5 O 2 ) phases, it was found that the o-phase became the lowest-in-energy for HfO 2 when the grain size was 3-5 nm (8-16 nm for Hf 0:5 Zr 0:5 O 2 Þ. 37 On the other hand, experimentally, Yurchuk et al 36 first reported that in Si: HfO 2 thin films, as the film thickness increased from 9 nm to 27 nm, the P r dropped from 24 C/cm 2 to 3.5 C/cm 2 . The similar inverse relation between P r and film thickness was also found in undoped HfO 2 38 and Hf 0:5 Zr 0:5 O 2 solid solution films.…”

Section: Origins Of Ferroelectricity In Hfo 2 -Based Materialsmentioning

confidence: 99%

See 1 more Smart Citation

Ferroelectric HfO₂-based materials for next-generation ferroelectric memories

2016

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Ferroelectric random access memory (FeRAM) based on conventional ferroelectric perovskites, such as Pb(Zr,Ti)O 3 and SrBi 2 Ta 2 O 9 , has encountered bottlenecks on memory density and cost, because those conventional perovskites suffer from various issues mainly including poor complementary metal-oxide-semiconductor (CMOS)-compatibility and limited scalability. Nextgeneration cost-efficient, high-density FeRAM shall therefore rely on a material revolution. Since the discovery of ferroelectricity in Si:HfO 2 thin films in 2011, HfO 2 -based materials have aroused widespread interest in the field of FeRAM, because they are CMOScompatible and can exhibit robust ferroelectricity even when the film thickness is scaled down to below 10 nm. A review on this new class of ferroelectric materials is therefore of great interest. In this paper, the most appealing topics about ferroelectric HfO 2 -based materials including origins of ferroelectricity, advantageous material properties, and current and potential applications in FeRAM, are briefly reviewed.

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Section: Origins Of Ferroelectricity In Hfo 2 -Based Materialsmentioning

confidence: 99%

Section: Origins Of Ferroelectricity In Hfo 2 -Based Materialsmentioning

confidence: 99%

Ferroelectric HfO₂-based materials for next-generation ferroelectric memories

2016

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“…Where hafnium based dielectrics must be in the orthorhombic phase to showcase ferroelectric characteristics 39 , there are also reports on negative capacitance using poly dielectric on 2D materials 40 . It is also shown that ferroelectricity decreases as the thickness of the material is reduced 41 . For a logic device, a ferroelectric material with near zero hysteresis may be required which is challenging because the ferroelectricity of these materials is dependent on their thickness with larger thickness leading to higher ferroelectricity).…”

Section: Channel and Gate Engineeringmentioning

confidence: 98%

Scaling Challenges for Advanced CMOS Devices

Jacob

Xie

Sung

et al. 2017

Int. J. Hi. Spe. Ele. Syst.

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The economic health of the semiconductor industry requires substantial scaling of chip power, performance, and area with every new technology node that is ramped into manufacturing in two year intervals. With no direct physical link to any particular design dimensions, industry wide the technology node names are chosen to reflect the roughly 70% scaling of linear dimensions necessary to enable the doubling of transistor density predicted by Moore's law and typically progress as 22nm, 14nm, 10nm, 7nm, 5nm, 3nm etc. At the time of this writing, the most advanced technology node in volume manufacturing is the 14nm node with the 7nm node in advanced development and 5nm in early exploration. The technology challenges to reach thus far have not been trivial. This review addresses the past innovation in response to the device challenges and discusses in-depth the integration challenges associated with the sub-22nm non-planar finFET technologies that are either in advanced technology development or in manufacturing. It discusses the integration challenges in patterning for both the front-end-of-line and back-end-of-line elements in the CMOS transistor. In addition, this article also gives a brief review of integrating an alternate channel material into the finFET technology, as well as next generation device architectures such as nanowire and vertical FETs. Lastly, it also discusses challenges dictated by the need to interconnect the ever-increasing density of transistors.

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“…7 Recently, phase stabilization of a noncentrosymmetric and ferroelectric orthorhombic phase (space group Pbc2 1 ) in HfO 2 -based films has also been claimed, in contrast to the previously mentioned crystalline phases, which are all centrosymmetric, offering the promise of novel applications of phase stabilized HfO 2 . [8][9][10][11][12][13][14][15] Various doping or alloying schemes, which utilize the addition of other metal oxides into thin HfO 2 films, such as ZrO 2 , Al 2 O 3 , SiO 2 , rare earth oxides, and alkaline earth oxides, with the goal of stabilization of the metastable higher-k phases, have been thoroughly investigated. [16][17][18][19][20][21][22][23] Another approach that may offer a viable method to engineer the phase of pure HfO 2 is by depositing a metal gate on top of a thin HfO 2 film and then subjecting the film stack to a postmetal deposition anneal (PMA).…”

Section: Introductionmentioning

confidence: 99%

Engineering crystallinity of atomic layer deposited gate stacks containing ultrathin HfO2 and a Ti-based metal gate: Effects of postmetal gate anneal and integration schemes

Consiglio¹,

Tapily²,

Clark³

et al. 2014

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

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In this study, the authors examined the effects of different annealing schemes on crystallinity in atomic layer deposition (ALD) grown Ti-containing metal gates and ultrathin ALD HfO 2 high-k dielectric layers, and corresponding electrical results in metal oxide semiconductor capacitor (MOSCAP) devices. The authors investigated the effect of a postmetal deposition anneal (PMA) on the underlying HfO 2 , which was deposited using either a standard ALD process or a process which utilized a cyclical deposition and annealing scheme (termed DADA). The effect of the starting substrate surface, either chemically grown SiO 2 or H-terminated Si, on HfO 2 crystallinity was also studied. For 40 cycle ALD HfO 2 ($32 Å ) with a TiN overlayer, a transition from an amorphous state to a cubic phase was observed with the application of a PMA treatment. Evidence of the orthorhombic phase of HfO 2 with some level of texturing was observed for 40 cycle DADA processed films annealed with a TiN cap. Concomitantly a cubic (111) texture was observed for TiN deposited on DADA processed HfO 2 and subjected to a PMA. Suppression of crystallinity for HfO 2 deposited on H-terminated Si and annealed with a TiN layer was observed which illustrates the need for an adequate nucleation layer for uniform grain growth and increased atomic ordering. The authors also investigated metal gate stacks with a bilayer of TiN overlying Ti which showed reflections from both cubic TiN and hexagonal TiN 0.3 in the as-deposited state and after annealing clear evidence of silicidation (TiSi x ) was observed. In MOSCAP structures with 40 cycle ALD HfO 2 and a TiN overlayer subjected to a PMA, although the cubic phase of HfO 2 was stabilized, there was no associated improvement in device scaling. This study highlights the importance of the initial crystalline state and nucleation of HfO 2 as well as the thermal stability of the capping metal layer material when engineering dielectric layer crystallinity by means of a postmetal cap anneal. For ultrathin HfO 2 integrated in advanced metal oxide semiconductor structures, the benefits of the stabilization of a higher-k phase through postmetal gate anneal may not be fully realized due to increased leakage along grain boundaries or decrease in effective k due to changes in the lower-k interfacial layer.

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Impact of layer thickness on the ferroelectric behaviour of silicon doped hafnium oxide thin films

Cited by 170 publications

References 26 publications

Ferroelectric HfO₂-based materials for next-generation ferroelectric memories

Ferroelectric HfO₂-based materials for next-generation ferroelectric memories

Scaling Challenges for Advanced CMOS Devices

Engineering crystallinity of atomic layer deposited gate stacks containing ultrathin HfO2 and a Ti-based metal gate: Effects of postmetal gate anneal and integration schemes

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Impact of layer thickness on the ferroelectric behaviour of silicon doped hafnium oxide thin films

Cited by 170 publications

References 26 publications

Ferroelectric HfO2-based materials for next-generation ferroelectric memories

Ferroelectric HfO2-based materials for next-generation ferroelectric memories

Scaling Challenges for Advanced CMOS Devices

Engineering crystallinity of atomic layer deposited gate stacks containing ultrathin HfO2 and a Ti-based metal gate: Effects of postmetal gate anneal and integration schemes

Contact Info

Product

Resources

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Ferroelectric HfO₂-based materials for next-generation ferroelectric memories

Ferroelectric HfO₂-based materials for next-generation ferroelectric memories