|TGI 40, thermal gas injector mounted on DN40 CF (O.D. 2.75") flange||
The Thermal Gas Injector – TGI – is a heated injector tube for the insertion of high vapor pressure materials or gases from an external gas reservoir or gas handling system into a vacuum chamber under high to ultra-high vacuum conditions (i.e. pressures less than 1x10-5 mbar). The TGI provides full compatibility with all UHV systems and standard III-V- molecular beam epitaxy.
A high temperature cracking zone close to the nozzle is offered as an option. The high temperature cracker can be operated up to 1400°C. It allows defined thermal decomposition of the injected gas.
The nozzle on top of the injector tube comprises a specially designed shower head gas distributor produces an adequate angle gas beam for uniform gas distribution on the substrate.
Gas connector side with all metal valve and pneumatic valves.
Various customer speciﬁed gas connectors like VCR, DN16CF, Swagelock, KF or other interfaces are provided. We also offer complete gas cabinet solutions as shown in the figure below.
We offer complete Gas Injection systems with customer speciﬁc design. The Gas Injection system is usually built up in a cabinet as for example shown on the right. Turbo molecular pumping and throughout gas line heating as well as mass-flow controlling, pneumatic valve operation, purification etc. are included. The gas lines and the all metal valves are typically bake-able up to 180°C.
|Gas cabinet with gas reservoir, purifies, mass-flow controllers, valves, heated gas-lines, pumping and control system.|
A typical applications for the TGI are listed in the table below. An example is the injection of NH3 for ammonium based growth of nitrides, or the injection of O2 for the growth of oxides.
The TGI is also well suited for in-situ etching applications using AsBr3 , Cl2 , HCl or Br2. The typical operation pressure is about 1x10-5 mbar.
|TGI standard version (TGI):|
|Al||MBE growth of III-V and GaN||DMEAAl|
|As||n-doping SiGe||AsH3 in H2|
|B||p-doping SiGe||B2H6 in H2|
|Br||etching of GaAs||AsBr3|
|C||SiC growth||SiH3CH3 in H2|
|Cl||etching of GaAs||HCl, AsCl3, Cl2|
|Ga||MBE growth of III-V and GaN||TEGa|
|In||MBE growth of III-V and GaN||TMIn|
|Mg||p-doping of Nitrides||CP2Mg|
|O||growth of Oxides||O2 or O3|
|P||n-doping SiGe||PH3 in H2|
|Si||MBE growth of SiGe||SiH4 or Si2H6|
|TGI version with cracker (TGI-C):|
|As||MBE growth of Arsenides||AsH3 or TBAs|
|N||MBE growth of Nitrides||NH3|
|P||MBE growth of Phosphides||PH3 or TBP|
The TGI is compatible with most MBE systems worldwide, e.g. Riber, Oxford Instruments/VG Semicon, Varian, Eiko, DCA, Veeco/ Applied Epi and Omicron. By specifying the system type or cell model number, we can supply a fully compatible TGI for your system.
For other systems please specify mounting ﬂange, in vacuum length, in vacuum diameter, substrate size and the distance from cell oriﬁce to the substrate.
Downward looking or horizontal operation is possible. If you want a special design for your speciﬁc needs, please contact us for more information. A sketch with the deﬁnition of dimensions is shown in the figure below.
Different types of gas line connectors are available: DN16CF ﬂange, VCR, Swagelock and others on request. Please specify the gas connector.
The standard gas conductor tube material is tantalum. For special requirements other materials like PBN, Al2O3, quartz, molybdenum and PG are available. Please specify the gas conductor material on your order.
An integrated high temperature cracking zone is offered as an option. A water cooling shroud is recommended for high temperature operation especially for thermal cracking option. Generally the gas injector is operated by a leak valve or pneumatic switching valve from the gas supply system. Therefore an integrated
shutter is not needed, but available optionally e.g. for very rapid gas ﬂow interruptions.
|C = thermal cracking zone
K = integrated water cooling shroud
S = integrated shutter
We provide DC power supplies and PID controllers for the TGI. The power supplies are compatible with most common AC supplies (Europe, China, Japan, USA, etc.).
For information on power supplies and temperature controllers please ask. We provide as standard a 20A cable set, including 6m power cable 2x2,5 mm² (bakeable 170°C) and 6m TC extension cable - type C (bakeable 250°C), ready-to-connect. We also offer high-temperature bake-able tapes (up to 400°C) with special lengths on request.
|Filament type||Ta or Mo ﬁlament in PBN support rings|
|Gas line||Ta, PBN, Al2O3, Quartz, Mo and PG; other materials on request|
|Thermocouple||Chromel/Alumel (type K), optional W5%Re/W26%Re (type C)|
||DN16CF ﬂange, VCR, Swagelock; others on request|
|Options||integrated thermal cracking zone (C)
integrated water cooling shroud (K),
integrated shutter (S)
|Schematic drawing of the Thermal Gas Injector TGI
(drawing shows TGI 40)
For general information on CF mounting flanges see Flange and Gasket dimensions.
|[mm] / [mm]||[W] / [A]||Product code|
|TGI||40||C-||K-||S**-||LxxxD35||cell: 25/ 2.5
||cell: PS 15-10
cracking zone: PS 70-10
|TGI||63||C-||K-||S**-||LxxxD35||cell: 25/ 2.5
||cell: PS 15-10
cracking zone: PS 70-10
|*||specify sample diameter and source-to-sample distance for aperture diameter|
|**||rotary shutter possible on same flange|
|***||specify UHV length L with order|
e.g. TGI 40-C-K-L250D35
is a thermal gas injector on DN40 CF ﬂange with integrated thermal cracking zone, water cooling shroud, in-vacuum length 250 mm and a diameter of 35 mm.