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 Doping Source SUSI-D 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-D assembly |
The most remarkable feature of the SUSI-D 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-D silicon parts: filament arch, base plate, shielding tube, top plate |
ApplicationThe SUSI-D is used for Si epitaxy (especially growth of high quality thin Si layers), Si doping in III-V MBE and doping in Si MBE. |
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Operation and ResultsThe 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. |
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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-D |
Several publications base on samples grown with SUSI-D sources. Please have a look at section References / List of Publications.
Technical data |
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Filament type | high purity monocrystalline silicon filament ρ>1000 Ω*cm (highly doped silicon on request) |
Filament shielding | filament completely shielded with silicon parts |
Thermocouple | W5%Re/W26Re (type C) |
Operating temperature | max. filament temperature 1400°C (limited by Si melting point) |
Bakeout temperature | 250°C |
Electrical contacts | water-cooled (4x Swagelok fitting connection O.D. 6mm); water flow min. 30 l/h |
Cooling | separate water (or LN2) cooling shroud |
Options | integrated rotary shutter (S) |
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Schematic drawing of the Silicon Sublimation Doping Source SUSI-D (drawing shows SUSI-D 63-S) |
For general information on CF mounting flanges see Flange and Gasket dimensions.
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[mm] / [mm] | [W] / [A] | [Å/min] | Product code | ||||
SUSI-D | 40 - | LxxxD36 | 250 / 55 | 2 | PS 20-76 | ||
SUSI-D | 63 - | S - | LxxxD55 | 500 / 80 | 7 | PS 15-100 |
* | rotary shutter possible on same flange |
** | maximum growth rate at 100m distance |
*** | specify UHV length L with order |
Product code:
e.g. SUSI-D 63-S-L310D56
is a silicon sublimation doping source on DN63 CF-flange with shutter, in-vacuum length 310 mm and diameter 55 mm.