Mapping the surface phase diagram of GaAs(001) using droplet epitaxy

Zheng, Changxi; Hannikainen, K.; Niu, Yuran; Tersoff, J.; Gomez, D.; Pereiro, J.; Jesson, D. E.

doi:10.1103/physrevmaterials.3.124603

Cited by 5 publications

(4 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is possible to solve the evolution Equation ( 5) with the initial condition h(x, 0) = H utilizing standard methods of functional analysis in presence of a forcing term. [38] We assume the continuity of 𝜇 (neglecting lateral corrugation) and neglect mass flow at the corners, so that we enforce 𝜕 2 h∕𝜕 x2 = 0 and 𝜕 3 h∕𝜕 x3 = 0 when x =± L where L = L∕𝜆 * . One may first compute the stationary solution hs ( x) of Equation ( 5) given by…”

Section: Surface Diffusion and Eigenmodesmentioning

confidence: 99%

\partial ^2 \tilde{h}/ \partial \tilde{x}^2 \! = \!0

and

$\partial ^3 \tilde{h}/ \partial \tilde{x}^3 \!

…”

Section: Surface Diffusion and Eigenmodesmentioning

confidence: 99%

See 1 more Smart Citation

Morphological Relaxation of Strained Epitaxial Films for Stripe‐Geometry Devices

Hannikainen,

Deprat,

Gourhant

et al. 2024

Adv Materials Technologies

View full text Add to dashboard Cite

One of the major issues when reducing the channel length in strained transistors is the stress relaxation that significantly degrades the carriers mobility. A new morphological evolution is reported here, describing the relaxation of a strained epitaxial film deposited on a pattern characterized by stripe geometry, both paradigmatic of two‐dimensional (2D) like systems, and characteristic of many devices. The thermodynamic surface diffusion framework accounting for elasticity and capillarity is investigated. The former is solved in two dimensions thanks to the Airy formalism. The resulting dynamical Schrödinger‐like equation governing the film shape evolution is then solved thanks to a decomposition on eigenmodes. It reveals different developments depending upon the system's geometric parameters and the time scale. Mass transfer occurs toward the relaxed areas and creates a ridge at the nanolayers edges, controlled by the geometry and the scale of the structure. These results allow to refine the potential control of electronic properties via the geometry of a system.

show abstract

Section: Surface Diffusion and Eigenmodesmentioning

confidence: 99%

\partial ^2 \tilde{h}/ \partial \tilde{x}^2 \! = \!0

and

$\partial ^3 \tilde{h}/ \partial \tilde{x}^3 \!

…”

Section: Surface Diffusion and Eigenmodesmentioning

confidence: 99%

Morphological Relaxation of Strained Epitaxial Films for Stripe‐Geometry Devices

Hannikainen,

Deprat,

Gourhant

et al. 2024

Adv Materials Technologies

View full text Add to dashboard Cite

show abstract

“…It is possible to solve the evolution equation ( 4) with the initial condition h(x, 0) = H utilizing standard methods of functional analysis in presence of the forcing term related to the energy inhomogeneity (see a similar problem in [25]). We assume the continuity of µ (neglecting lateral corrugation) and neglect mass flow at the corners, so that we enforce ∂ 2 h/∂ x2 = 0 and ∂ 3 h/∂ x3 = 0 when x = ± L where L = L/λ * .…”

Section: Surface Diffusion Framework and Eigenmodesmentioning

confidence: 99%

Shape relaxation of epitaxial mesa for finite-size strain-engineering

R.¹,

Favre²,

Deprat³

et al. 2022

Preprint

View full text Add to dashboard Cite

Silicon-Germanium (Si 1−x Ge x ) layers are commonly used as stressors in the gate of MOSFET devices. They are expected to introduce a beneficial stress in the drift and channel regions to enhance the electron mobility. When reducing the gate lateral size, one of the major issues is the stress relaxation which results in a significant decrease in the electron mobility. We report a new morphological evolution of a strained epitaxial SiGe nanolayer on a silicon gate (mesa) driven by strain inhomogeneity due to finite-size effects. Unlike the self-induced instability of strained films, this evolution arises here due to the elastic inhomogeneity originating from the free frontiers. We analyze the growth dynamics within the thermodynamic surface diffusion framework accounting for elasticity and capillarity, the former being solved in two dimensions thanks to the Airy formalism. The resulting dynamical equation is solved with a decomposition on eigenmodes, and reveals different developments depending upon the mesa geometric parameters. Mass transfer occurs towards the relaxed areas and creates a beading at the nanolayers free surface with either a W or V shape as a function of time and geometry. The evolution is then controlled by the proportions of the structure as well as its scale.

show abstract

“…During droplet epitaxy, liquid droplets initially form on the substrate surface through a III-column element molecular beam, and an As flux is subsequently used for the crystallization with the droplets into the various III-As nanostructures including quantum dots [10,11], quantum rings [12,13] and nanoholes [14][15][16][17] by controlling the intensity of As flux and the crystallization temperature. The formation mechanism of various nanostructures has been studied by some theoretical models which found that the diffusions of III-column atoms and As atoms determined the final geometry of the nanostructures [18][19][20][21][22][23][24][25]. Taking the GaAs system as an example, the bulk diffusion of As atoms into Ga droplets play a key role in the formation of QDs shape in the case of high intensity of As flux and low temperature [26].…”

Section: Introductionmentioning

confidence: 99%

The structural symmetry of nanoholes upon droplet epitaxy

2021

Nanotechnology

View full text Add to dashboard Cite

Nanoholes obtained by droplet epitaxy has been intensively investigated as an important material platform for the fabrication of nanodevices due to their unique topology. However, the final fabricated nanoholes are very difficult to achieve a highly symmetric circular structure, and usually have two or four gaps in the sidewall of the holes. Here we have presented a developed model to inquire into the reasons for the formation of the gaps at the periphery of nanoholes and discuss how to improve the structural symmetry of the nanoholes. It is found that the anisotropic interface diffusion of As atoms decomposed by substrate can result in the formation of the gaps. In order to improve the symmetry of final nanostructures, we can minimize the interval time between deposition of Ga droplets and open operation of As flux, and set up a multistep growth procedure by changing the intensity of As flux or growth temperature.

show abstract

Mapping the surface phase diagram of GaAs(001) using droplet epitaxy

Cited by 5 publications

References 41 publications

Morphological Relaxation of Strained Epitaxial Films for Stripe‐Geometry Devices

Morphological Relaxation of Strained Epitaxial Films for Stripe‐Geometry Devices

Shape relaxation of epitaxial mesa for finite-size strain-engineering

The structural symmetry of nanoholes upon droplet epitaxy

Contact Info

Product

Resources

About