Abstract
Ion microprobe mass analysis is said to be non-destructive from a macroscopic viewpoint. Howe ever, it is essentially destructive as it is accompanied by sputtering effect. When thin film or surface layer are to be analyzed, high sensitive analysis with an infinitisimal amount of specimen and with the highest possible accuracy is especially desirable.
In order to increase the sensitivity of the ion microprobe mass analyzer, we developed a new second ary ion extracter with Pierce type electrode. It is constructed of a Pierce electrode, an extracting electrode, an accelerating electrode and an electrostatic lens assembly.
As an application of the method, an aluminum film was analyzed by the ion microprobe mass analyzer. The film was prepared by the evaporation of pure aluminum using a crucible of boron nitride. Assuming that the minimum detectable signal is about twice the noise level, the detection limit of boron in aluminum is a few ppm. In this case, the sputtering rate was about 5Å/s. The detection limit of bulk is on the order of several tenth of ppb.
