SiGe: An attractive material for post-CMOS processing of MEMS

Sedky, Sherif

doi:10.1016/j.mee.2007.05.055

Cited by 15 publications

(6 citation statements)

References 38 publications

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“…Such precise spatial control of the material properties opens a route for the fabrication of complex devices based on alloy microstructures such as graded-index optical waveguides and lens, metasurfaces, Bragg gratings, laterally modulated compositional heterostructures, full-spectrum solar cells, multispectral photodetectors, and graded-base transistors, for example. The unexposed material and solute-poor undercladdings surrounding the laser-written regions can be selectively etched to release solute-rich microstripes of nanometer thickness (see Supporting Information, Figure S11), which could be used for the development of microbolometers, thermoelectric generators, and micro-electromechanical systems, where suspended microstructures are required for thermal isolation from the substrate or to allow for movement of parts . Furthermore, this laser-writing procedure could be applied to other multicomponent material systems, including epitaxially-grown crystalline SiGe films, metal alloys (Ni–Cu, Sb–Bi), ternary semiconductors (Al 1– x Ga x As, Hg 1– x Cd x Te, Cd 1– x Zn x Te), ceramics (Al 2 O 3 –Cr 2 O 3 , V 2 O 3 –Cr 2 O 3 ), and organic crystals ( p -chlorobromobenzene– p -dibromobenzene), which behave as pseudobinary systems, having isomorphous phase diagrams similar to that of SiGe alloys …”

Section: Resultsmentioning

confidence: 99%

Laser-Driven Phase Segregation and Tailoring of Compositionally Graded Microstructures in Si–Ge Nanoscale Thin Films

Aktaş

MacFarquhar

et al. 2020

ACS Appl. Mater. Interfaces

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The ability to manipulate the composition of semiconductor alloys on demand and at nanometer-scale resolutions is a powerful tool that could be exploited to tune key properties such as the electronic band gap, mobility, and refractive index. However, existing methods to modify the composition involve altering the stoichiometry by temporal or spatial modulation of the process parameters during material growth, limiting the scalability and flexibility for device fabrication. Here, we report a laser processing method for localized tailoring of the composition in amorphous silicon−germanium (a-SiGe) nanoscale thin films on silicon substrates, postdeposition, by controlling phase segregation through the scan speed of the laser-induced molten zone. Laser-driven phase segregation at speeds adjustable from 0.1 to 100 mm s −1 allows access to previously unexplored solidification dynamics. The steady-state spatial distribution of the alloy constituents can be tuned directly by setting the laser scan speed constant to achieve indefinitely long Si 1−x Ge x microstructures, exhibiting the full range of compositions (0 < x < 1). To illustrate the potential, we demonstrate a photodetection application by exploiting the laser-written polycrystalline SiGe microstripes, showing tunability of the optical absorption edge over a wavelength range of 200 nm. Our method can be applied to pseudobinary alloys of ternary semiconductors, metals, ceramics, and organic crystals, which have phase diagrams similar to those of SiGe alloys. This study opens a route for direct laser writing of novel devices made of alloy microstructures with tunable composition profiles, including graded-index waveguides and metasurfaces, multispectral photodetectors, full-spectrum solar cells, and lateral heterostructures.

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Section: Resultsmentioning

confidence: 99%

Laser-Driven Phase Segregation and Tailoring of Compositionally Graded Microstructures in Si–Ge Nanoscale Thin Films

Aktaş

MacFarquhar

et al. 2020

ACS Appl. Mater. Interfaces

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“…GILD combines the Laser Thermal Processing technique [5][6][7] with the incorporation of Ge atoms from a precursor gas chemisorbed on the surface sample. The processing technique uses a XeCl excimer laser whose 20 ns pulses at 308 nm are strongly absorbed over a depth of about 7 to 10 nm in Si, Ge and SiGe.…”

Section: Methodsmentioning

confidence: 99%

Pseudomorphic and relaxed SiGe/Si(001) layer synthesis by gas immersion laser doping (GILD)

Kociniewski

Fossard

Perrossier

et al. 2011

Phys. Status Solidi (c)

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We report on the synthesis of SiGe layers on silicon by using a pulsed laser processing technique (Gas Immersion Laser Doping) where GeCl4 gas molecules are adsorbed on the surface and further incorporated into the Si top layer by a pulsed laser induced melt/regrowth process. In‐situ real‐time measurements of the transient reflectivity of a laser diode reveal that SiGe is formed. Structural characterization of the SiGe layers by X‐ray diffraction evidences that pseudomorphic SiGe layers are obtained. Moreover, we demonstrate that Ge concentration saturates at about 16% in the strained layers and that a relaxation process occurs when samples are exposed to 4000 laser pulses or more (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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“…Many researchers have performed studies comparing the effect of thermal and laser annealing on the properties of silicon alloys (Parr et al 2002;Sedky 2007). These studies reported laser/annealed films to have better device properties than thermal annealed.…”

Section: Introductionmentioning

confidence: 99%

Laser annealing of sputter-deposited a-SiC and a-SiC x N y films

et al. 2011

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This work describes the laser annealing of a-SiC and a-SiC x N y films deposited on (100) Si and quartz substrates by RF magnetron sputtering. Two samples of a-SiC x N y thin films were produced under different N 2 /Ar flow ratios. Rutherford backscattering spectroscopy (RBS), Raman analysis and Fourier transform infrared spectrometry (FTIR) techniques were used to investigate the composition and bonding structure of as-deposited and laser annealed SiC and SiC x N y films.

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SiGe: An attractive material for post-CMOS processing of MEMS

Cited by 15 publications

References 38 publications

Laser-Driven Phase Segregation and Tailoring of Compositionally Graded Microstructures in Si–Ge Nanoscale Thin Films

Laser-Driven Phase Segregation and Tailoring of Compositionally Graded Microstructures in Si–Ge Nanoscale Thin Films

Pseudomorphic and relaxed SiGe/Si(001) layer synthesis by gas immersion laser doping (GILD)

Laser annealing of sputter-deposited a-SiC and a-SiC x N y films

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