Nucleation and growth of atomic layer deposited HfO2 gate dielectric layers on chemical oxide (Si–O–H) and thermal oxide (SiO2 or Si–O–N) underlayers

Green, Martin A.; Ho, M.-Y.; Busch, B.; Wilk, G. D.; Sorsch, T.; Conard, Thierry; Brijs, Bert; Vandervorst, Wilfried; Räisänen, Petri I.; Muller, David A.; Bude, M.; Grazul, John

doi:10.1063/1.1522811

Cited by 291 publications

(231 citation statements)

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“…Such deposition is not straightforward and it has been found that the deposition behavior of a high-k layer can be highly dependent upon the starting surface. 5 Moreover, we have observed that metallorganic chemical vapor deposition ͑MOCVD͒ of HfO 2 on various starting surfaces results in the formation of an interfacial layer ͑IL͒ underneath the high-k layer, which obviously influences device performance. Furthermore, if this IL becomes too thick, the 1 and sub-1 nm equivalent oxide thicknesses ͑EOTs͒ targeted in the ITRS roadmap cannot be reached.…”

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confidence: 99%

Composition and Growth Kinetics of the Interfacial Layer for MOCVD HfO[sub 2] Layers on Si Substrates

Elshocht

Caymax

Gendt

et al. 2004

J. Electrochem. Soc.

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To boost MOS transistor performance, thickness of the gate dielectric is continuously scaled down. This results in an increase of gate tunneling leakage current, which at some point prevents further downscaling. Desired parameters of alternative materials to SiO 2 are a higher dielectric constant ͑high-k materials͒, stability, and compatibility with silicon. A general observation for one of the prime candidates, HfO 2 , is formation of an interfacial layer between the silicon and the high-k material that limits scalability because of its low k-value. Hence, a thorough study of the formation of this layer and its contribution to the equivalent oxide thickness is of utmost importance. We studied the composition and growth kinetics of the interfacial layer formed during the deposition of HfO 2 by metallorganic chemical vapor deposition using O 2 and tetrakis-diethylamidohafnium as precursor. We found the composition and thickness of the interfacial layer to be dependent on the deposition parameters as well as on the starting surface. The layer's composition is hafnium silicate-like and its thickness increases as a function of deposition time and temperature. It is therefore controlled by deposition of the HfO 2 layer. SiO 2 has been used for decades as the gate isolator material in complementary metal-oxide semiconductor ͑CMOS͒ technology. Downscaling of the gate dielectric to improve device performance is reaching physical limits where the gate material consists of only a few atomic layers, resulting in unacceptably high leakage currents.1 Reducing the leakage current through nitridation prolongs the lifespan of SiO 2 , 2 but according to the International Technology Roadmap for Semiconductors ͑ITRS͒, industry will from 2005 on abandon SiO 2 as a gate material and start replacing it with materials having a higher dielectric constant ͑high-k materials͒. 3 The urgent need for these new materials has resulted in extensive research on several high-k candidates, such as Al 2 O 3 , ZrO 2 , HfO 2 , ZrSiO x , HfSiO x , etc. At present, Hf-based materials are the most likely candidates.Si and SiO 2 as a gate material are chemically perfectly compatible, which was, among others, one of the reasons for choosing Si and for the success of the silicon semiconductor industry. For high-k materials possible interactions between Si ͑both substrate and polySi electrode͒ and the high-k material are an additional concern needing to be addressed. For example, these interactions can result in silicide formation at the high-k/polysilicon interface, as has been observed for ZrO 2 . 4 In addition, there is also an important difference in processing; whereas SiO 2 as gate dielectric is grown simply by oxidation of the silicon substrate, high-k materials have to be deposited. Such deposition is not straightforward and it has been found that the deposition behavior of a high-k layer can be highly dependent upon the starting surface.5 Moreover, we have observed that metallorganic chemical vapor deposition ͑MOCVD͒ of HfO 2 on various starting s...

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confidence: 99%

Composition and Growth Kinetics of the Interfacial Layer for MOCVD HfO[sub 2] Layers on Si Substrates

Elshocht

Caymax

Gendt

et al. 2004

J. Electrochem. Soc.

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“…This component ratio of SC1 solution was developed by M. L. Green, etc., 23 and was modified in our previous work to be an effective method to grow interfacial layer for ALD of high quality HfO 2 . 26 Multi-angle spectroscopic ellipsometry (J.…”

Section: Methodsmentioning

confidence: 99%

“…OH termination of Si is crucial for the chemical attachment of metal precursors onto Si surface. 1,[18][19][20][21][22] It was found that the density of -OH groups on Si surface has an effect on the atomic surface roughness and dielectric leakage current of HfO 2 23 Ozone based wet chemical oxidation and ozonated water spraying are widely used in industry for ALD growth of HfO 2 . 24,25 The growth of the interfacial layer was controlled by ozone concentration in water.…”

mentioning

confidence: 99%

Atomic Layer Deposition of High Quality HfO₂Using In-Situ Formed Hydrophilic Oxide as an Interfacial Layer

Han

Pan

et al. 2014

ECS J. Solid State Sci. Technol.

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High-quality HfO 2 cannot be grown directly on Si substrate using atomic layer deposition (ALD), and an interfacial oxide layer is needed. Traditionally, interfacial oxide layer is formed either in SC1 solution (2 NH 4 OH: 4 H 2 O 2 : 200 H 2 O) or by ozonated water spraying. A highly hydrophilic SiO 2 interfacial layer was in-situ formed in the ALD chamber using 1 cycle of ozone and water. The HfO 2 deposited on this interfacial layer showed great growth linearity. The gate leakage current is comparable to that formed using chemical oxide as the interfacial layer. The capacitance-voltage (C-V) curves have negligible frequency dispersion and hysteresis, which suggest high quality in both the interface and electrical properties. The in-situ formation of hydrophilic interfacial layer have advantages over the traditional interfacial layer. This might be useful for formation of interfacial layer on sophisticated 3-D MOS structures such as FinFETs and nanowire FETs. In addition, the chemical oxidation step can be eliminated from the integrated circuits manufacturing processes, which is economically beneficial to the industry. After a decade of investigation, atomic layer deposition (ALD) of high dielectric constant (high-k) material HfO 2 became the mainstream manufacturing processing in semiconductor industry. This is because the superior quality of HfO 2 films obtained by ALD. ALD provides precise control of film thickness and uniformity at the atomic scale, due to its self-limiting surface reaction. However, not all surfaces are suitable for ALD deposition.Extensive work has been done to explore the proper interface conditions for ALD of metal oxides. It is widely accepted that non-oxide like Si surface creates barrier for initial cycles of ALD, results in growth incubation period.1-3 Researchers such as E. P. Gusev, etc. and R. L. Puurunen, etc. explored the ALD nucleation of ZrO 2 , Al 2 O 3 , TiO 2 and HfO 2 on Si surface, and proved that comparing to nucleation on SiO 2 surface, nucleation on H-terminated Si surface is characterized by non-uniformity, island-like morphology, poor metal oxide qualities, and metal diffusion at high temperature.4-11 Plus, underlying SiO 2 would grow at the Si/metal oxide interface at moderate temperature, which is harmful to the scaling of MOS devices.12,13 This has been proved by infrared spectroscopy.14 There are also researches on nucleation of HfO 2 on Si (110) and Si (111), 15 and Ge surface, 16,17 which is a potential substrate material with high mobility. L. In this work, we report an ALD-based in-situ formation of SiO 2 interfacial layer using one cycle of ozone and water. The interfacial layer formed is highly hydrophilic, and the ALD HfO 2 grown on this interfacial layer has comparable qualities to HfO 2 grown on SC1 chemical oxide. The interfacial layer was in-situ formed in the ALD chamber. This method might be used in sophisticated 3-D MOS structures because ALD allows molecules to be deposited on the surface that cannot be accessible using other methods. In addition...

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“…SC1 cleaning is commonly used in silicon IC processing and is known to produce an OH terminated SiO 2 surface [8,9]. (997) 2.2.…”

Section: Introductionmentioning

confidence: 99%

Kelvin Force Microscopy Characterization of Corona Charged Dielectric Surfaces

Marinskiy¹,

Edelman²,

Snider

2014

Acta Phys. Pol. A

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Nucleation and growth of atomic layer deposited HfO2 gate dielectric layers on chemical oxide (Si–O–H) and thermal oxide (SiO2 or Si–O–N) underlayers

Cited by 291 publications

References 16 publications

Composition and Growth Kinetics of the Interfacial Layer for MOCVD HfO[sub 2] Layers on Si Substrates

Composition and Growth Kinetics of the Interfacial Layer for MOCVD HfO[sub 2] Layers on Si Substrates

Atomic Layer Deposition of High Quality HfO₂Using In-Situ Formed Hydrophilic Oxide as an Interfacial Layer

Kelvin Force Microscopy Characterization of Corona Charged Dielectric Surfaces

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Nucleation and growth of atomic layer deposited HfO2 gate dielectric layers on chemical oxide (Si–O–H) and thermal oxide (SiO2 or Si–O–N) underlayers

Cited by 291 publications

References 16 publications

Composition and Growth Kinetics of the Interfacial Layer for MOCVD HfO[sub 2] Layers on Si Substrates

Composition and Growth Kinetics of the Interfacial Layer for MOCVD HfO[sub 2] Layers on Si Substrates

Atomic Layer Deposition of High Quality HfO2Using In-Situ Formed Hydrophilic Oxide as an Interfacial Layer

Kelvin Force Microscopy Characterization of Corona Charged Dielectric Surfaces

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Atomic Layer Deposition of High Quality HfO₂Using In-Situ Formed Hydrophilic Oxide as an Interfacial Layer