Grooved insulator to reduce leakage current

A method of manufacturing a plasma source, comprising:

• forming ceramic material into a green body having a shape of an insulator, with one or more grooves formed in the green body;
• sintering the green body to form the insulator;
• disposing an insulator, with one or more grooves defined in an insulator surface thereof, in contact with a first electrode;
• disposing a second electrode in contact with the insulator to form a cavity that is bounded by a surface of the first electrode, a surface of the second electrode, and the insulator surface;
• providing an inlet gas line configured to introduce one or more gases into the cavity through at least one of the first electrode and the second electrode;
• and
• providing an electrical coupling across the first and second electrodes, wherein:
• the first and second electrodes are isolated from electrically contacting one another, by the insulator;
• the cavity is configured such that when the one or more gases are introduced into the cavity and the electrical coupling provides RF energy across the first and second electrodes, a plasma forms within the cavity;
• and
• the one or more grooves defined in the insulator surface are configured such that deposition of plasma sputtered material from the first or second electrode surfaces on the insulator surface is interrupted at the one or more grooves.

A method of manufacturing a plasma source, comprising:

• forming ceramic material into a green body having a shape of an insulator;
• sintering the green body to form the insulator;
• machining the insulator to form one or more grooves in an insulator surface thereof,
• disposing the insulator in contact with a first electrode;
• disposing a second electrode in contact with the insulator to form a cavity that is bounded by a surface of the first electrode, a surface of the second electrode, and the insulator surface;
• providing an inlet gas line configured to introduce one or more gases into the cavity through at least one of the first electrode and the second electrode;
• and
• providing an electrical coupling across the first and second electrodes, wherein:
• the first and second electrodes are isolated from electrically contacting one another, by the insulator;
• the cavity is configured such that when the one or more gases are introduced into the cavity and the electrical coupling provides RF energy across the first and second electrodes, a plasma forms within the cavity;
• and
• the one or more grooves defined in the insulator surface are configured such that deposition of plasma sputtered material from the first or second electrode surfaces on the insulator surface is interrupted at the one or more grooves.