Metal-Organic Precursor Injector

The MOPI source is specifically designed for the controlled deposition of metal-organics, such as Titanium Tetraisopropoxide (TTIP) or Vanadium Oxytriisopropoxide (VTIP). The flow rate/flux is feedback controlled using a capacitance manometer, Eurotherm PID controller and motorised UHV metering valve, to provide rapid and reproducible injection control. When the MOPI source is filled with TTIP and combined with a Valved Cracker Source or Low Temperature (LTEC) effusion cell for Strontium (Sr), Strontium Titanate (STO) can be grown, for wafers up to ø300 mm.  

 The injector has integrated heating and cooling to ensure a stable temperature and a reliable flux throughout the growth process. Both the source tank and gas manifold (to the injector) are equipped with separate heating jackets and a temperature controller, to enable separate temperature set-points to be assigned to the source tank and gas manifold. An elevated temperature for the manifold is essential to prevent material condensation, whilst the source tank temperature determines the flow rate.  

 The source tank is mounted to a separate (run/pump) manifold equipped with two electropneumatic shut-off valves, which are synchronized to allow delivery of the precursor gas to either the growth chamber (run) or to the pump station (pump). This feature ensures a stable pressure/flow rate is reached prior to growth, and secondly, allows conditioning after exchanging the source in order to achieve the pre-determined parameters required for reproducible stoichiometric growth.  

 The MOPI source can be software-controlled, for remote operation via the PC and recipe creation for pre-programmed growth.