The fundamental characteristics of a newly developed Cs surface ionization ion source are described. This Cs ion source has two main features. One of the features is the use of the chemically stable compound CsCl as the ion source material, which can be handled safely. Another feature is the utilization of electron bombardment to heat the prous tungsten ion emitter, which results in high ion current density.
The angular ion intensity amounts to 10
4μA/sr at the ion emitter temperature of 1500°C. This value leads to the maximum sample ion current of 10 μA, when it is used as a primary gun of SIMS. The Cs ion current intensity is stabilized within ±0.6 % for 30min., by means of controlling heating power of the ion emitter.
With this ion gun the SIMS depth profile of As is carried out with detection limit of -10
13 atoms/cm
3. From the spatial resolution of secondary electron image, the minimum beam diameter is estimated to be about 2 to 3 μm.
抄録全体を表示