Molecular Beam Epitaxy

Growth & Synthesis (Physical depositions of thin films)

Molecular beam epitaxy (MBE) is a growth technique for the deposition of high quality and high purity epitaxial layers on suitable substrates. It is mainly used for the growth of semiconductors, oxides and organic materials.

Fully automated MBE systems for the growth of advanced, compound semiconductor heterostructures, composed of compounds based on III-Arsenide, III-nitride, Si, SiC, Ge, C semiconductor nanostructures with sub-nanometer control of the film thicknesses. The MBE system is used to make nanostructures, including quantum dots and nanowires, and epitaxially layered structures and heterostructures, for the fabrication of lasers, photodetectors, light-emitting diodes and other optoelectronic devices. The MBE systems are equipped with a series of in-situ analytical characterization tools for continuous monitoring of the growth process.

Thermally produced atomic or molecular beams of the constituent materials migrate in Ultra High Vacuum (UHV) environment until impinge on a heated substrate where they are incorporated. The growth rate is generally very slow, of the order of one monolayer (ML) per second, allowing a ML control of the deposition.

The UHV environment allows for the use of diagnostic techniques during the growth as the reflection high energy electron diffraction (RHEED) and the integration of the growth system with UHV surface characterization techniques. When combined with the referred ability to perform in-situ high-resolution structural and electronic diagnostics of the films as they are being deposited, MBE provides the ideal scenario for understanding many of the fundamental structural and physical properties of ultrathin inorganic and organic film systems.

In some cases, MBE systems should be prepared not only for in-situ characterization but for in operando as well, in order to study the dynamics of growth. This should lead to the design of compact, element or material specific and flexible systems. In operando studies are particularly interesting for understanding catalytic processes.

provided at NFFA-Europe laboratories by:

CNR-IOM (TS)

Italy

C2N-CNRS

France

CSIC-ICMAB

Spain

FORTH

Greece

JCNS @MLZ

Germany

EURONANOLAB

France

CNR-IOM (TS)

Italy

III-V and II-VI MBE

Applications

III-V and II-VI MBE

Source

For III/V materials: effusion cells for Ga , Al, In, As, Si (n-type dopant), GaTe (n-type dopant) and Be (p-type dopant), RF Plasma source for N; for II/VI materials: effusion cells for Zn, Cd, Se, Te

Sample

III/V materials: GaAs, AlGaAs, InGaAs epitaxial layers and nanowires; II/VI materials: ZnSe, ZnCdSe epitaxial layers and nanowires; In mounted; dimension up to 3" diameter; T range: up to 700°C for III/V materials and up to 500°C for II/VI materials

Environment

UHV

Monitors

RHEED gun 10 kV

Ancillary Techniques

Metallization chamber for deposition of Au and Al at room temperature

Additional Tools

XPS analysis chamber with Al Kα source

CNR-IOM (TS)

Italy

Oxide MBE

Applications

MBE of metal oxide ferromagnetic, antiferromagnetic, superconducting, insulating, ferroelectric, multiferroic ; MBE masked conducting deposition

Source

Sources for Oxide-MBE growth: 3 high temperature effusive cells (up to 1500°C); 3 conventional effusive cells; 2 low temperature effusive cells; ozone/oxygen deposition pressure up to 10-5 mbar; 3d, 4d, 4f metals, organic molecular magnets, MgO, Al2O3, NiO; perovskite structure compounds ABO3: ( La-Sr)(Co-Cu-Ti-Zn)O3, (Ba-K)(Cu-Bi)O3, (Ba-Sr)(Ti-Zr)O3, (La-Ba)(Mn-Fe-Ni-Co)O3, Bi(Fe-Mn)O3; Spinel structure compound AB2O4: ZnFe2O4, Fe3O4 Sources for MBE Masked conducting deposition: Au, Pd, Fe, Co, Mn conductive metals, up to 5 e-bombardment evaporators.

Sample

For Oxide-MBE growth: dimensions up to 10x10mm2; T up to 800K For MBE Masked conducting deposition: dimensions up to 5x5mm2; T range: 35-300K; annealing temperature up to 950K

Environment

For Oxide-MBE growth: base pressure down to 10-9 mbar

Monitors

For Oxide-MBE growth: 2 RHEED guns, electron energy 10 kV, spot size 100 micron diameter; RHEED software analysis KSA-400 For MBE Masked conducting deposition: LEED/Auger spectroscopy OCI BDL800IR; transport measurements Keithley 6487

Additional Tools

For MBE Masked conducting deposition. XPS Chamber with: Al and Mg K-alfa X-rays at 1486.7 and 1253.7 eV, electrostatic hemispherical analyzer (radius 200 mm), T range 25-300 K; MOKE magnetometry with: HeNe Thorlabs HNL020L laser 632.8 nm, linear polarization, T range 30-340 K, maximum H-field 0.55 T in UHV, 0.75 T in air, minimum H-field step 0.3 mT, pole face diameter 76 mm, frequency filter HINDS optical chopper 50KHz, Si, Ge photodiode HINDS DET 200-004, spectral range 350-1100 nm

CNR-IOM (TS)

Italy

High Mobility MBE

Applications

High Mobility MBE

Source

Effusion cells for Ga (2x), Al, In, As, As cracker. Doping: Si (n-type) and C (p-type) direct-heat filament

Sample

III/V materials: GaAs/AlGaAs 2D electron gases with low-T electron mobility up to 8X106 cm2/Vs, metamorphic In0.75GaAs/In0.75AlAs quantum wells with low-T electron mobility up to 5X105 cm2/Vs, photonic structures, self-assembled quantum dots on planar and patterned surfaces; dimension up to 2" diameter; T range: up to 700 C; possibility of In-free mounting

Environment

UHV

Monitors

RHEED gun 15 kV

Additional Tools

Magnetotransport facility

CSIC-ICMAB

Spain

SiGe MBE

Applications

MBE SiGe epitaxy

Source

Si e-beam and Ge effusion cell for deposition at typical fluxes ~0.05nm/s; dopant sources for C, B, and Sb with typical fluxes up to ~0.0005nm/s

Sample

Substrate sizes up to 10cm (4") diameter wafers, also possible from 1 to 4 cm2 square substrates; In-free mounting; T range: up to 950° C

Environment

Base pressure in growth chamber in 10-10 mbar range

Monitors

RHEED gun 30 kV allows observation for big substrates

Additional Tools

Ex-situ optical and electrical basic characterization possible (f.i., ellipsometry, Raman, and Hall measurements), no analysis software available

FORTH

Greece

III-As MBE

Applications

MBE of heterostructures & nanostructures, dots and NWs for nano and optoelectronic applications

Source

K-cells for Ga (2), Al (2), As, In, Si, Be

Sample

Dimension up to 3"

Environment

UHV

Monitors

RHEED 15 KeV; mass spectrometer 1-300 amu

Ancillary Techniques

Preparation chamber with outgas heater and Auger spectrometer

FORTH

Greece

Group IV elements MBE

Applications

c-SiC growth, SiC NWs

Source

K-cells for Ga, Ge, Al; C2H2 gas sources; e-guns for Si and C

Sample

Dimension up to 3"

Environment

UHV

Monitors

RHEED 30 KeV; mass spectrometer 1-300 amu

Ancillary Techniques

Preparation chamber with outgas heater and Auger spectrometer, substrate heater up to 1200oC

FORTH

Greece

III-Nitrides MBE

Applications

MBE of heterostructures & nanostructures, dots and NWs for nano and optoelectronic applications

Source

K-cells for Ga, Al, In, Si; additional Si sublimation source; N2 RF plasma source; NH3 possible too

Sample

Dimension up to 3"

Environment

UHV

Monitors

RHEED 15 KeV; mass spectrometer 1-200 amu

Ancillary Techniques

Preparation chamber with outgas heater

JCNS @MLZ

Germany

Thin film MBE

Applications

Thin film fabrication: metal films, oxides, nitrides, multilayers and heterostructures. Detailed information is available at https://mlz-garching.de/mbe

Source

4 high temperature effusion cells (up to 1800°C); 2 low temperature effusion cells (up to 1400°C); RF atom plasma source for oxygen/nitrogen (plasma up to 600W) with deposition pressure up to 10e-5 mbar; 2 e-guns with 4 crucibles each; examples for evaporation materials: Fe, Co, Au, Ag, Ni, Sr, Ti, La, Mn, Nb, Pt, Cu, Cr, other materials on request.

Sample

Dimensions up to 2". Typical sample size 10x10mm^2 and 20x20mm^2

Environment

UHV, base pressure below 8e-10 mbar; sample temperature up to 1000°C; sample rotation (0-60rpm)

Monitors

RHEED, electron energy max. 20 kV, RHEED software analysis KSA-400; LEED up to 1 kV; AES up to 5 kV, spectrum up to 1000eV; residual gas analyzer (quadrupole mass spectrometer); quartz micro balance

Ancillary Techniques

Script based programming of sample preparation/growth. Special transfer chamber allowing the transfer and measurement of thin films under UHV conditions with MNR (Installation 6, Characterisation) at a pressure better than 10-9 mbar at room temperature and in magnetic fields up to 300 mT.

Additional Tools

Additional sample characterization in the laboratory available like Atomic Force Microscopy (AFM), see installation 4, characterisation AFM.

C2N-CNRS

France

III-V MBE 2DEGs and quantum cascade structures

Applications

III-V MBE: 2DEGs and GaAs/AlGaAs quantum cascade structures

Source

Effusion cells for Ga (2x), Al (2x), In, As cracker. Doping: Si (n-type) and C (p-type) direct-heat filaments

Sample

III/V materials: GaAs/AlGaAs 2D electron gases with low-T electron mobility up to 2.5X106 cm2/Vs, with a possibility of 2DEGs on sub-micron membranes, GaAs/AlGaAs quantum cascade structures; dimension up to 2" diameter; T range: up to 700°C; possibility of In-free mounting

Environment

UHV

Monitors

RHEED gun 12 kV

Additional Tools

Magnetotransport facility

C2N-CNRS

France

III-V MBE with PL, FTIR and magnetotransport

Applications

MBE growth of a large range of III-V material: microcavities, quantum dots, electro-optical devices

Source

7 effusion cells (2xGa, 2xAl, In, Si, Be), As, P, Sb cracker cells, N plasma source

Sample

Up to 2" wafer, GaAs, InAs, InP, GaSb substrates, T up to 900°C

Environment

Base pressure down to 10-10 torr

Monitors

RHEED gun 12 kV

Ancillary Techniques

Outgassing chamber

Additional Tools

PL setup (down to 77K), FTIR microscope, magnetotransport facility

C2N-CNRS

France

III-N MBE

Applications

MBE of nitride based nanowires

Source

5 effusion cells (Ga, Al, In, Si, Mg); N plasma source

Sample

Wafer dimension: 1/4 of 2"; T up to 850°C

Environment

UHV

Monitors

RHEED gun 15 kV

C2N-CNRS

France

III-V MBE microcavities, quantum dots and electro-optical devices

Applications

MBE growth of a large range of III-V material: microcavities, quantum dots, electro-optical devices

Source

7 effusion cells (2xGa, 2xAl, In, Si, Be), As, P, Sb cracker cells, N plasma source

Sample

Up to 2" wafer; GaAs, InAs, InP, GaSb substrates; T up to 900°C

Environment

Base pressure down to 10-10 torr

Monitors

RHEED gun 12 kV

Ancillary Techniques

Outgassing chamber

C2N-CNRS

France

III-V MBE diluted magnetic semiconductors

Applications

MBE growth of III-V diluted magnetic semiconductors

Source

7 effusion cells (Ga, Al, In, P, Si, Be, Mn), As cracker cell

Sample

Up to 2" wafer; GaAs, InAs, InP substrates; T up to 700°C

Environment

UHV

Monitors

RHEED gun 15 kV

Ancillary Techniques

Outgassing chamber

C2N-CNRS

France

III-V MBE nanowires

Applications

MBE growth of III-V nanowires, equipped with a gold cell in the growth chamber for catalyst

Source

6 effusion cells (Ga, Al, In, Si, Be, Au), As, P cracker cells

Sample

Up to 2" wafer; GaAs, InAs, InP substrates; T up to 700°C

Environment

UHV

Monitors

RHEED gun 15 kV

Ancillary Techniques

Outgassing chamber

EURONANOLAB

France

MBE at EURONANOLAB - IEMN

EURONANOLAB

France

MBE at EURONANOLAB - LAAS

EURONANOLAB

France

MBE at EURONANOLAB - PoliFAB