Electrical characterisation of high-k materials prepared by atomic layer CVD

Due to increasing speed, density and number of signal paths in integrated circuits, motivations for high density capacitors capable of quickly sourcing large amounts of current have led to many design and fabrication investigations. This work outlines continued efforts to achieve devices which meet these stringent requirements and are compatible with standard silicon fabrication processes as well as silicon interposer technologies. Previous work has been further developed resulting in devices exhibiting greater capacitance values by employing geometries which maximize surface area. The Atomic Layer Deposition (ALD) of thin layered high K materials, such as Hafnium Oxide, as opposed to previous silicon-dioxide based devices effectively increased the capacitance per unit area of the structures. This paper outlines the design, fabrication, and testing of high density micro-machined embedded capacitors capable of quickly sourcing (i.e. risetimes greater than 100A/nsec) high currents (i.e. greater than 100A). These devices were successfully simulated then tested using a standard ringdown procedure. Generally, the resulting device characterization found during testing stages strongly correlates to the expected simulated device behavior. Subsequent descriptions and design challenges encountered during fabrication, testing and integration of these passive devices are outlined, as well as potential device integration and implementation strategies for use in silicon interposers. The modification and revision of several device generations is documented and presented. Increased device capacitive density, maximized current capabilities and minimized effects of series inductance and resistance are presented. These resulting thin, capacitive structures exhibit compatibility with Si interposer technology.

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Mechanism of the HF Pulse in the Thermal Atomic Layer Etch of HfO2 and ZrO2: A First Principles Study

10.26434/chemrxiv.11310860 ◽

2019 ◽

Author(s):

Rita Mullins ◽

Suresh Natarajan ◽

Simon D. Elliott ◽

Michael Nolan

Keyword(s):

First Principles ◽

Ligand Exchange ◽

Elevated Temperatures ◽

Atomic Layer ◽

Level Control ◽

Exchange Reactions ◽

Nanoscale Device ◽

High K ◽

Reaction Models ◽

High K Materials

<div>HfO2 and ZrO2 are two high-k materials that are important in the down-scaling of semiconductor devices. Atomic level control of material processing is required for fabrication of thin films of these materials at nanoscale device sizes. Thermal Atomic Layer Etch (ALE) of metal oxides, in which up to one monolayer of the material can be removed, can be achieved by sequential self-limiting fluorination and ligand-exchange reactions at elevated temperatures. However, to date a detailed atomistic understanding of the mechanism of thermal ALE of these technologically important oxides is lacking. In this paper, we investigate the hydrogen fluoride pulse in the first step in the thermal ALE process of HfO2 and ZrO2 using first principles simulations. We introduce Natarajan-Elliott analysis, a thermodynamic methodology, to compare reaction models representing the self-limiting (SL) and continuous spontaneous etch (SE) processes taking place during an ALE pulse. Applying this method to the first HF pulse on HfO2 and ZrO2 we found that thermodynamic barriers impeding continuous etch are present at ALE relevant temperatures. We performed explicit HF adsorption calculations on the oxide surfaces to understand the mechanistic details of the HF pulse. A HF molecule adsorbs dissociatively on both oxides by forming metal-F and O-H bonds. HF coverages ranging from 1.0 0.3 to 17.0 0.3 HF/nm2 are investigated and a mixture of molecularly and dissociatively adsorbed HF molecules is present at higher coverages. Theoretical etch rates of -0.61 0.02 Å /cycle for HfO2 and -0.57 0.02 Å /cycle ZrO2 were calculated using maximum coverages of 7.0 0.3 and 6.5 0.3 M-F bonds/nm2 respectively (M = Hf, Zr).</div>

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Radiation Tolerance and Charge Trapping Enhancement of ALD HfO2/Al2O3 Nanolaminated Dielectrics

Materials ◽

10.3390/ma14040849 ◽

2021 ◽

Vol 14 (4) ◽

pp. 849

Author(s):

Dencho Spassov ◽

Albena Paskaleva ◽

Elżbieta Guziewicz ◽

Vojkan Davidović ◽

Srboljub Stanković ◽

...

Keyword(s):

Charge Trapping ◽

Atomic Layer ◽

Information Storage ◽

Radiation Tolerance ◽

Leakage Currents ◽

High K ◽

60Co Source ◽

Retention Characteristics ◽

High K Materials ◽

High K Dielectric

High-k dielectric stacks are regarded as a promising information storage media in the Charge Trapping Non-Volatile Memories, which are the most viable alternative to the standard floating gate memory technology. The implementation of high-k materials in real devices requires (among the other investigations) estimation of their radiation hardness. Here we report the effect of gamma radiation (60Co source, doses of 10 and 10 kGy) on dielectric properties, memory windows, leakage currents and retention characteristics of nanolaminated HfO2/Al2O3 stacks obtained by atomic layer deposition and its relationship with post-deposition annealing in oxygen and nitrogen ambient. The results reveal that depending on the dose, either increase or reduction of all kinds of electrically active defects (i.e., initial oxide charge, fast and slow interface states) can be observed. Radiation generates oxide charges with a different sign in O2 and N2 annealed stacks. The results clearly demonstrate a substantial increase in memory windows of the as-grown and oxygen treated stacks resulting from enhancement of the electron trapping. The leakage currents and the retention times of O2 annealed stacks are not deteriorated by irradiation, hence these stacks have high radiation tolerance.

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Atomic Layer Deposition of High-k Insulators on Epitaxial Graphene: A Review

Applied Sciences ◽

10.3390/app10072440 ◽

2020 ◽

Vol 10 (7) ◽

pp. 2440 ◽

Cited By ~ 2

Author(s):

Filippo Giannazzo ◽

Emanuela Schilirò ◽

Raffaella Lo Nigro ◽

Fabrizio Roccaforte ◽

Rositsa Yakimova

Keyword(s):

Atomic Layer Deposition ◽

Critical Role ◽

Atomic Layer ◽

Epitaxial Graphene ◽

Organic Monolayers ◽

Layer Deposition ◽

High K ◽

Deposited Metal ◽

High K Materials ◽

The Impact

Due to its excellent physical properties and availability directly on a semiconductor substrate, epitaxial graphene (EG) grown on the (0001) face of hexagonal silicon carbide is a material of choice for advanced applications in electronics, metrology and sensing. The deposition of ultrathin high-k insulators on its surface is a key requirement for the fabrication of EG-based devices, and, in this context, atomic layer deposition (ALD) is the most suitable candidate to achieve uniform coating with nanometric thickness control. This paper presents an overview of the research on ALD of high-k insulators on EG, with a special emphasis on the role played by the peculiar electrical/structural properties of the EG/SiC (0001) interface in the nucleation step of the ALD process. The direct deposition of Al2O3 thin films on the pristine EG surface will be first discussed, demonstrating the critical role of monolayer EG uniformity to achieve a homogeneous Al2O3 coverage. Furthermore, the ALD of several high-k materials on EG coated with different seeding layers (oxidized metal films, directly deposited metal-oxides and self-assembled organic monolayers) or subjected to various prefunctionalization treatments (e.g., ozone or fluorine treatments) will be presented. The impact of the pretreatments and of thermal ALD growth on the defectivity and electrical properties (doping and carrier mobility) of the underlying EG will be discussed.

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Mechanism of the HF Pulse in the Thermal Atomic Layer Etch of HfO2 and ZrO2: A First Principles Study

10.26434/chemrxiv.11310860.v1 ◽

2019 ◽

Author(s):

Rita Mullins ◽

Suresh Natarajan ◽

Simon D. Elliott ◽

Michael Nolan

Keyword(s):

First Principles ◽

Ligand Exchange ◽

Elevated Temperatures ◽

Atomic Layer ◽

Level Control ◽

Exchange Reactions ◽

Nanoscale Device ◽

High K ◽

Reaction Models ◽

High K Materials

<div>HfO2 and ZrO2 are two high-k materials that are important in the down-scaling of semiconductor devices. Atomic level control of material processing is required for fabrication of thin films of these materials at nanoscale device sizes. Thermal Atomic Layer Etch (ALE) of metal oxides, in which up to one monolayer of the material can be removed, can be achieved by sequential self-limiting fluorination and ligand-exchange reactions at elevated temperatures. However, to date a detailed atomistic understanding of the mechanism of thermal ALE of these technologically important oxides is lacking. In this paper, we investigate the hydrogen fluoride pulse in the first step in the thermal ALE process of HfO2 and ZrO2 using first principles simulations. We introduce Natarajan-Elliott analysis, a thermodynamic methodology, to compare reaction models representing the self-limiting (SL) and continuous spontaneous etch (SE) processes taking place during an ALE pulse. Applying this method to the first HF pulse on HfO2 and ZrO2 we found that thermodynamic barriers impeding continuous etch are present at ALE relevant temperatures. We performed explicit HF adsorption calculations on the oxide surfaces to understand the mechanistic details of the HF pulse. A HF molecule adsorbs dissociatively on both oxides by forming metal-F and O-H bonds. HF coverages ranging from 1.0 0.3 to 17.0 0.3 HF/nm2 are investigated and a mixture of molecularly and dissociatively adsorbed HF molecules is present at higher coverages. Theoretical etch rates of -0.61 0.02 Å /cycle for HfO2 and -0.57 0.02 Å /cycle ZrO2 were calculated using maximum coverages of 7.0 0.3 and 6.5 0.3 M-F bonds/nm2 respectively (M = Hf, Zr).</div>

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Optimized Al-doped TiO2 gate insulator for metal-oxide-semiconductor capacitor on Ge substrate

Journal of Materials Chemistry C ◽

10.1039/d0tc04725b ◽

2021 ◽

Author(s):

Dong Gun Kim ◽

Cheol Hyun An ◽

Sanghyeon Kim ◽

Dae Seon Kwon ◽

Junil Lim ◽

...

Keyword(s):

Metal Oxide ◽

Leakage Current ◽

Tio2 Film ◽

Single Layer ◽

Atomic Layer ◽

Metal Oxide Semiconductor ◽

Gate Insulator ◽

Oxide Semiconductor ◽

High K ◽

Metal Oxide Semiconductor Capacitor

Atomic layer deposited TiO2- and Al2O3-based high-k gate insulator (GI) were examined for the Ge-based metal-oxide-semiconductor capacitor application. The single-layer TiO2 film showed a too high leakage current to be...

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Composition Quantification of Microelectronics Multilayer Thin Films by EDX: Toward Small Scale Analysis

MRS Proceedings ◽

10.1557/proc-1184-hh08-08 ◽

2009 ◽

Vol 1184 ◽

Cited By ~ 4

Author(s):

Thierry Conard ◽

Kai Arstila ◽

Thomas Hantschel ◽

Alexis Franquet ◽

Wilfried Vandervorst ◽

...

Keyword(s):

Gate Dielectric ◽

Small Scale ◽

Quantitative Composition ◽

Composition Analysis ◽

Multilayer Thin Films ◽

Large Area ◽

Fast Analysis ◽

Metal Gates ◽

High K ◽

High K Materials

AbstractIn order to continuously improve the performances of microelectronics devices through scaling, SiO2 is being replaced by high-k materials as gate dielectric; metal gates are replacing poly-Si. This leads to increasingly more complex stacks. For future generations, the replacement of Si as a substrate by Ge and/or III/V material is also considered. This also increases the demand on the metrology tools as a thorough characterization, including composition and thickness is thus needed. Many different techniques exist for composition analysis. They usually require however large area for the analysis, complex instrumentation and can be time consuming. EDS (Energy Dispersive Spectroscopy) when coupled to Scanning Electron Microscopy (SEM) has the potential to allow fast analysis on small scale areas.In this work, we evaluate the possibilities of EDS for thin film analysis based on an intercomparison of composition analysis with different techniques. We show that using proper modeling, high quality quantitative composition and thickness of multilayers can be achieved.

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