Insights for void formation in ion-implanted Ge

Darby, B. L.; Yates, B. R.; Rudawski, Nicholas G.; Jones, K. S.; Kontos, A.; Elliman, R. G.

doi:10.1016/j.tsf.2011.03.040

Cited by 40 publications

(34 citation statements)

References 23 publications

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“…[40][41][42][43][44] If the ion dose is further increased, the material will remain amorphous up to a dose of ;2.0 Â 10 15 cm À2 , but if the dose is increased just beyond this, the material will start to structurally decompose and exhibit "pore clusters," which nucleate at the free surface of the material. 25 It is important to note that the crystalline to amorphous transition appears to be necessary prior to the occurrence of nanostructuring; in other words, the material must first exhibit a bulk amorphous structure prior to any pore nucleation, though it is not understood why this is the case. If the dose is further increased, the pores (also interchangeably referred to as "voids" or "craters") completely cover and rupture the surface while becoming larger and somewhat elongated along the direction of the incident ions, generating a layer with the nanostructured morphology on top of a nonporous a-Ge layer.…”

Section: Basic Observations and Microstructural Evolutionmentioning

confidence: 99%

“…If the dose is further increased, the pores (also interchangeably referred to as "voids" or "craters") completely cover and rupture the surface while becoming larger and somewhat elongated along the direction of the incident ions, generating a layer with the nanostructured morphology on top of a nonporous a-Ge layer. 21,[24][25][26][27][28] As the dose further increases, the nanostructured layer experiences a large out-of-plane expansion with the individual pores continuing to elongate and the surface experiencing increased roughening; 24,25 an underlying a-Ge layer remains under the nanostructured layer, but while the thickness of the nanostructured layer continues to increase with increasing dose, the thickness of the underlying a-Ge layer remains relatively constant. This complete morphological evolution of Ge with increasing ion dose is presented schematically in Fig.…”

Section: Basic Observations and Microstructural Evolutionmentioning

confidence: 99%

“…This morphology as been variously referred to by many different labels over several decades of study as "voided," "porous," "nanoporous," "cratered," and "honeycomb," but for the purpose of this study, this morphology will be referred to as "nanostructured" as first termed by Romano et al 24 As previously mentioned, the structural decomposition of Ge due to ion beam modification has been extensively studied and characterized by several independent research groups over several decades. The process is known to be most sensitive to ion dose, 21,[24][25][26][27][28] specimen temperature during implantation, 20,27,29,30 and, most interestingly, the a) nature of the starting material prior to ion beam modification (amorphous versus crystalline). 28,31 However, while the structural decomposition of Ge has been studied and characterized empirically quite extensively, the fundamental understanding of nanostructuring due to ion beam modification remains a topic of debate.…”

Section: Introductionmentioning

confidence: 99%

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Nanostructured germanium prepared via ion beam modification

Rudawski

Jones

2013

J. Mater. Res.

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Nanostructured" germanium (Ge; also known as "voided," "porous," "nanoporous," "cratered," and "honeycomb" Ge) created via ion beam modification has been studied for many years. This work reviews the progress made in studying and characterizing the nanostructured morphology, particularly via the use of experimental techniques such as scanning electron microscopy, atomic force microscopy, and transmission electron microscopy. Specifically, the empirical observations of the structural evolution of Ge as a function of ion beam modification conditions are discussed with added emphasis placed on quantification of the microstructure. The experimental observations and microstructure quantification are further discussed in terms of the implications for proposed formation mechanisms of the nanostructured morphology. Potential uses of the nanostructured morphology in chemical sensor and energy storage applications and suggested future lines of research to further the fundamental understanding of nanostructuring in Ge using ion beam modification are also presented.

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Section: Basic Observations and Microstructural Evolutionmentioning

confidence: 99%

Section: Basic Observations and Microstructural Evolutionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Nanostructured germanium prepared via ion beam modification

Rudawski

Jones

2013

J. Mater. Res.

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“…Experimental data shows a rapid decrease of {311} defects in SiGe of only 20% Ge consistent with decreasing TED (11). Also high dose implants into Ge result in a porous structure that may result from dynamic Vac-dominated aggregation during the implant, but what happens to the Ints is not clear (12).…”

Section: Dopant-vacancy Interactionsmentioning

confidence: 88%

(Invited) Understanding Diffusion, Activation, and Related Phenomena in SiGe Alloys: Models and Challenges

Kennel

2013

ECS Trans.

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An effective diffusivity modeling approach is described that proposes scaling relations for point defect-mediated dopant diffusion to reflect how SiGe with a given Ge concentration differs from Si. Literature results from density functional theory calculations, statistical arguments, and kinetic lattice Monte Carlo simulations can be used to determine the expected scaling relations, which can be verified and adjusted later by comparisons to experimental data. Considerations for targeting of anneals for SiGe and Ge are given. Approaches to optimize annealing using millisecond anneals and nonequilibrium effects are discussed and expectations of behavior in SiGe are outlined. Additional uncertainties related to these SiGe-related behaviors in nanoscale materials are discussed. Improving Understanding via Process Modeling of SiGe MaterialsDevice structures incorporating SiGe within a Si platform have become more commonplace in the last decade (1). Including SiGe is often motivated by its beneficial carrier transport and electronic properties relative to pure Si. Careful control of stress may or may not be a crucial aspect of the engineering, depending on the application. Certainly the type of stress, whether biaxial or approximately uniaxial in nature, is a key determinant of band gap, mobility, and related electronic properties. Process modeling of diffusion, activation, and related phenomena in SiGe must comprehend the compositional and possibly stress states in the SiGe and Si layers. For mainstream use, continuum diffusion models will be the mainstay, but insight may be gained by studies with other approaches such as kinetic lattice Monte Carlo or density functional theory. An overview of relevant physics of SiGe will be discussed as a motivation for our approach at how we are building continuum diffusion models for dopants in SiGe. The traditional approach of acquiring a large database of diffusion experimental data and creating empirical models requires many resources. Here we discuss an approach that attempts to impose more structure on the compositional dependence to initially see the essential features. These forms might then be fitted to experimental data, and details modified, when a sufficiently wide database is available. Subsequently a discussion of annealing and activation of SiGe, including ideas projected from Si millisecond annealing and nonequilibrium approaches to achieving superactivation (activation exceeding solubility), will be discussed. Finally, a discussion of the relevance of nanosizes on diffusion and thermal transport will motivate the need for more attention to this growing area. 10.1149/05009.0233ecst ©The Electrochemical Society ECS Transactions, 50 (9) 233-243 (2012) 233 ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 138.251.14.35 Downloaded on 2015-03-20 to IP Trends in Physical Chemistry from Si through SiGe to GeWe wish to exploit the similarities between SiGe and Si as much as possible in order to sca...

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“…Generally, implantation leads to the formation of defects of different nature in the material (vacancy, dislocation, amorphization, etc.). High-dose implantations in Ge (>10 15 atoms/cm 2 ) have been reported to induce the formation of nanoporous structures [16][17][18][19][20][21][22][23][24][25]. Thus, ion implantation may be a simple way to produce a nanoporous semiconductor.…”

Section: Introductionmentioning

confidence: 99%

Nanoporous Ge thin film production combining Ge sputtering and dopant implantation

Toinin¹,

Portavoce²,

Hoummada³

et al. 2016

Nano Online

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In this work a novel process allowing for the production of nanoporous Ge thin films is presented. This process uses the combination of two techniques: Ge sputtering on SiO 2 and dopant ion implantation. The process entails four successive steps: (i) Ge sputtering on SiO 2 , (ii) implantation preannealing, (iii) high-dose dopant implantation, and (iv) implantation postannealing. Scanning electron microscopy and transmission electron microscopy were used to characterize the morphology of the Ge film at different process steps under different postannealing conditions. For the same postannealing conditions, the Ge film topology was shown to be similar for different implantation doses and different dopants. However, the film topology can be controlled by adjusting the postannealing conditions. 336

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Insights for void formation in ion-implanted Ge

Cited by 40 publications

References 23 publications

Nanostructured germanium prepared via ion beam modification

Nanostructured germanium prepared via ion beam modification

(Invited) Understanding Diffusion, Activation, and Related Phenomena in SiGe Alloys: Models and Challenges

Nanoporous Ge thin film production combining Ge sputtering and dopant implantation

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