Apparatus for detecting or monitoring for a chemical precursor in a high temperature environment
An apparatus and method are disclosed for monitoring and/or detecting concentrations of a chemical precursor in a reaction chamber. The apparatus and method have an advantage of operating in a high temperature environment. An optical emissions spectrometer (OES) is coupled to a gas source, such as a solid source vessel, in order to monitor or detect an output of the chemical precursor to the reaction chamber. Alternatively, a small sample of precursor can be periodically monitored flowing into the OES and into a vacuum pump, thus bypassing the reaction chamber.
1. A device configured for determining a concentration of a gas source comprising:
a solid source vessel, the solid source vessel comprising a solid precursor configured to be converted to a first gas precursor;
a gas line coupled to the solid source vessel, the gas line configured to move a first portion of the first gas precursor into a reaction chamber and move a second portion of the first gas precursor into a sampling port;
a RF source coupled to the sampling port, the RF source ionizing the first gas precursor;
an optical emissions spectrometer coupled to the RF source, the optical emissions spectrometer configured to obtain a light spectrum of the ionized first gas precursor; and
an exhaust pump coupled to the RF source and configured to exhaust the ionized first gas precursor;
wherein a concentration of the ionized first gas precursor is determined based on the light spectrum.
2. The device of claim 1 , further comprising a heater to heat a part of the gas line connected to the RF source.
3. The device of claim 1 , further comprising a plurality of valves to control a flow of the first gas precursor from the solid source vessel.
4. The device of claim 1 , wherein the RF source comprises at least one of: an inductively coupled plasma source; a capacitively coupled plasma source; a microwave source; or a hot filament gas ionizer.
5. The device of claim 1 , further comprising a flow restrictor disposed between the RF source and the exhaust pump.
6. The device of claim 1 , further comprising an optical fiber coupling the RF source to the optical emissions spectrometer.
7. The device of claim 6 , wherein the optical fiber comprises:
a light transmission section;
a purge gas channel;
an outer sheath;
a wide view fiber optic attached to the light transmission section; and
a purge nozzle attached to the outer sheath.
8. The device of claim 1 , further comprising a heated vacuum enclosure to hold at least the solid source vessel.
9. The device of claim 8 , further comprising a flow restrictor within the heated vacuum enclosure.
10. The device of claim 1 , further comprising an inert gas source configured to provide an inert carrier gas for the first gas precursor.