Ion source and a method for in-situ cleaning thereof
An ion source and method of cleaning are disclosed. One or more heating units are placed in close proximity to the inner volume of the ion source, so as to affect the temperature within the ion source. In one embodiment, one or more walls of the ion source have recesses into which heating units are inserted. In another embodiment, one or more walls of the ion source are constructed of a conducting circuit and an insulating layer. By utilizing heating units near the ion source, it is possible to develop new methods of cleaning the ion source. Cleaning gas is flowed into the ion source, where it is ionized, either by the cathode, as in normal operating mode, or by the heat generated by the heating units. The cleaning gas is able to remove residue from the walls of the ion source more effectively due to the elevated temperature.
1. A method of extending a lifetime of an ion source, the method comprising:
introducing a feed gas containing a desired molecular species to a chamber of the ion source;
activating an indirectly heated cathode of the ion source for ionizing the feed gas and generating ions of the desired molecular species;
activating a heating unit disposed proximate at least one wall of the ion source; and
maintaining a temperature of the chamber above 800° C. so as to reduce condensation of the ions of the desired molecular species on walls of the ion source.
2. The method of claim 1 , wherein said heating unit is chosen from a group consisting of a lamp and a resistive heater.
3. The method of claim 1 , wherein the desired molecular species comprises carborane.
4. The method of claim 1 , wherein the desired molecular species comprises a hydride comprising boron.
5. The method of claim 1 , wherein the desired molecular species comprises germanium and hydrogen.
6. The method of claim 1 , wherein the desired molecular species comprises phosphine.
7. The method of claim 1 , wherein the desired molecular species comprises ethane, propane, pyrene or bibenzyl.
8. The method of claim 1 , further comprising monitoring a temperature within the chamber and activating the heating unit based on the monitored temperature.
9. The method of claim 1 , wherein the ion source comprises a plurality of walls and the heating unit is disposed in a recess in a wall of the ion source.
10. The method of claim 1 , wherein the ion source comprises a plurality of walls and at least one of the walls is a heating unit.
11. The method of claim 1 , further comprising:
introducing cleaning gas to the ion source so as to generate reactive cleaning gas species, wherein the cleaning gas comprises at least one of hydrogen containing gas; chlorine containing gas; fluorine containing gas; nitrogen containing gas or oxygen containing gas.