ALD is similar to CVD except that the ALD reaction occurs at lower temperature and it is broken into two half-reactions, keeping the precursor materials separated during the reaction. The separation of the precursors is important to achieve a self-limiting surface reaction to enable precise thickness control and ensure uniform coatings and compactness even in complicated 3D structures.
ALD has a rich history in microelectronics. It is studied as a potential technique to deposit high-k (high permittivity) gate oxides, high-k memory capacitor dielectrics, ferroelectrics, and metals and nitrides for electrodes and interconnects. The motivation for high-k oxides comes from the problem of high tunnelling currents through the currently used SiO2 MOSFET gate dielectric when it is downscaled to a thickness of 1,0 nm and below. With the high-k oxide, a thicker gate dielectric can be made for the required capacitance density, thus the tunnelling current can be reduced through the structure.
Importantly, the number of materials that can be prepared by ALD has tremendously increased in the past decade and noble metals, ternary oxides, metal fluorides, nitrides, selenides and inorganic-organic hybrid materials are already introduced opening up new opportunities for numerous industrial applications.
TDMAHf for hafnium oxides
TMAl for aluminium oxides
Deposition at 50-250° C
Deposited film thicknesses from 0.1-20nm
Up to 2” wafer
E-2 mbar range base pressure
LUND + MAX IV
Sweden
ALD Savannah-100
Thermal ALD of high k oxides
TDMAHf for hafnium oxides
TMAl for aluminium oxides
Deposition at 75-250° C
Deposited film thicknesses from 0.1-50nm
Up to 4” wafer
E-2 mbar range base pressure
LUND + MAX IV
Sweden
ALD - Fiji
Thermal and Plasma ALD of oxides and titanium nitrides
TDMAHf for hafnium oxides
TMAl for aluminium oxides
TEMAZr for Zirconium oxides
BDEASi for Siicon oxides
TEMATi for titanium nitrides
Deposition at 50-400° C
Deposited film thicknesses from 0.1-100nm
Up to 8” wafer
E-2 mbar range base pressure
PSI
Switzerland
Picosun R200 ALD @ Laboratory for Micro- and Nanotechnology
Atomic Layer Deposition
Gas, liquid, solid, Ir-precursor, WF6, SiH4, Al-precursor, H2 and O2 (plasma source), H20 (+ Ar/N2 as inert gas)
H2/O2 plasma up to 2000W
4" wafer size, solid samples only, should not be prone to O2 plasma
Coarse vacuum down to 1 mbar, N2/Ar atmosphere, temperatures up to ~370°C
Loadloack with sample transfer, manual placement in chamber
CSIC-CNM
Spain
Atomic Layer Deposition Savannah 200
Deposition of very thin dielectric layers (at the moment Al2O3, HfO2 and TiO2) with excellent thickness control and conformality. For layers with thickness from 5nm to 50nm.
Al2O3: TMA and H2O or O3
HfO2: TDMAH and H2O or O3
TiO2: TDMAT and H2O
Thermal ALD, with temperature ranges typically between 150ºC - 350ºC
For flat samples up to 200mm diameter, typically for semiconductor substrates, and preferably those free of metals (or metal traces) other than Al, Ti or W.
remote or presential (but not hands-on)
interaction by telephone or e-mail
EURONANOLAB
France
ALD at EURONANOLAB - CEITEC
EURONANOLAB
France
ALD at EURONANOLAB - IMT
C2N-CNRS
France
ALD Fiji 200
Al2O3 (100-250°c) standard
SiO2 (150-250°c) standard
HfO2 (100-250°c) standard
TiO2 (100-250°c) standard
ICP power: 300W
Gas Line: N2
Gas Line: O2
Gas Line: NH3
Max sample size: 8 inches
Max sample size: 6.5 mm height
In SEM a beam is scanned over a sample surface while a signal from secondary or back-scattered electrons is recorded. SEM is used to image an area of the sample with nanometric resolution, and also to measure its composition, crystallographic phase distribution and local texture.
Electron-beam lithography is a direct write nanopatterning technique utilizing a finely focused electron beam in order to write nanoscale patterns on special e-beam resists in two and three dimensions. Compared to other nanostructuring methods, it stands out for its high level of flexibility and resolution and reasonable patterning speed.
RIE is used to etch various materials under vacuum in the presence of reactive ions. The sample to be etched is placed in a vacuum chamber and gas is injected into the process chamber via a gas inlet in the top electrode. The lower electrode is negatively biased and a single RF plasma source determines both the ion density and their energy.
PL is a non-contact, non-destructive method of probing the electronic structure of materials, often used in the context of semiconductor devices to determine the bandgap energy, the composition of heterostructures, the impurity levels, the crystal quality, and to investigate recombination mechanisms.
XRD provides non-destructive information on the structural order of a material. At large scattering angles XRD permits to identify different crystal phases and to quantify lattice distances and crystalline volume fractions. At low angles of incidence the surface roughness of a single crystal and the thickness of a deposition layer can be obtained.
