JPS6430142A - Microwave ion source - Google Patents

Abstract

PURPOSE:To prevent a microwave introduction part from being damaged by disposing a plurality of microwave introduction window parts and a microwave introduction port holding part at the microwave introduction part in a cavity part for plasma generation. CONSTITUTION:A plurality of microwave introduction window parts 122a, 122a' and a microwave introduction port holding part 123 are disposed at a microwave introduction part 122 in a cavity part for plasma generation 1. Recessed parts are formed in respective spaces between the microwave introduction window parts 122a and 122a'. The microwave introduction port holding part 123 is provided with a screening matter at a position where the microwave introduction window parts 122a, 122a' are screened against high-speed reverse electrons which flow in the reverse direction from an ion drawing electrode. Also the part 123 functions to introduce microwaves and plasma to a central position of the cavity part for plasma generation 1. Hence the high-speed reverse electrons can be prevented from impinging on the microwave introduction window parts, and so the microwave introduction window parts can be prevented from being damaged.