Thermal sublimation of silicon from high purity intrinsic or highly doped Si filament
Excellent growth of thin silicon layers
Compatible with most MBE systems
Water-cooled electrical contacts
Inner filament shielding with pure silicon parts
No ceramic parts in the hot zone
The Silicon Sublimation Source SUSI was developed for growing thin Si layers, short period Si/Ge superlattices and Si/SiGe heterostructures. It allows for growth of thin epitaxial Si layers with a crystal quality not otherwise possible by evaporation from effusion cell crucibles.
Main parts of the SUSI assembly
The most remarkable feature of the SUSI is its arch-shaped, free-standing silicon filament, which is directly heated by electrical current and exclusively surrounded by silicon shielding parts of highest purity, effectively shielding the hot filament.
High purity SUSI silicon parts: filament arches, base plates, shielding tubes, top plates
The SUSI is used for Si epitaxy (especially growth of high quality thin Si layers), Si doping in III-V MBE and doping in Si MBE. (For Silicon Sublimation Sources more optimized for doping applications please refer to our specialized source type SUSI-D.)
Several Publications base on samples grown with SUSI.
Operation and Results
The figure on the right compares the growth rates of SUSI 40 and SUSI 63, measured as a function of the electrical current through a new silicon filament.
Over the operation time the filament becomes thinner, whereby the growth rates at a given current gradually increases. The current settings should therefore be reduced from time to time to keep the flux rate constant.
|SUSI silicon growth rate as a function of the electrical current
|The next figure shows the RHEED oscillations measured during Si homoepitaxy on a (001) oriented silicon substrate at 20keV electron energy and a substrate temperature of 400°C.
From the RHEED oscillation diagram a growth rate of 1.22 monolayers per minute (1.66 Å/min) can be determined. The low decay of the oscillation amplitude indicates ultra pure growth conditions.
RHEED oscillations measured during Si homoepitaxy with a SUSI
Several publications based on samples grown with SUSI are listed in section References / List of Publications.
|high purity monocrystalline silicon filament ρ>1000 Ω*cm (highly doped silicon on request)
|filament completely shielded with silicon parts
|W5%Re/W26Re (type C)
|max. filament temperature 1400°C (limited by Si melting point)
|water-cooled (4x Swagelok fitting connection O.D. 6mm); water flow min. 30 l/h
|separate water (or LN2) cooling shroud
|integrated rotary shutter (S)
|Schematic drawing of the Silicon Sublimation Source SUSI
(drawing shows SUSI 63)
For general information on CF mounting flanges see Flange and Gasket dimensions.
|[mm] / [mm]
|[W] / [A]
|255 / 55
|405 / 80
|1100 / 145
|rotary shutter possible on same flange
|maximum growth rate at 100 mm distance
|specify UHV length L with order
e.g. SUSI 63-S-L310D56
is a silicon sublimation source on DN63 CF-flange with shutter, in-vacuum length 310 mm and diameter 55 mm.
The following list provides suggestions for related products. For additional product suggestions or more detailed information, please contact us.
|Silicon Sublimation Doping Source
|Standard Effusion Cell
|Electron Beam Evaporator
|Cooling Shrouds CS
|Beam Flux Monitor BFM
|Quartz Crystal Monitor QCM