AVS 49th International Symposium
    Applied Surface Science Monday Sessions
       Session AS-MoM

Paper AS-MoM9
Secondary Ion Emission from Thick Organic Films: Influence of Primary Ion Bombardment Conditions

Monday, November 4, 2002, 11:00 am, Room C-106

Session: SIMS
Presenter: R. Kersting, Tascon GmbH, Germany
Authors: E. Tallarek, Tascon GmbH, Germany
F. Kollmer, ION-TOF GmbH, Germany
B. Hagenhoff, Tascon GmbH, Germany
R. Kersting, Tascon GmbH, Germany
Correspondent: Click to Email
Our ongoing studies focus on the secondary ion emission from thick organic layers under different primary ion bombardment conditions. As model analyte system spin coated layers of the polymer additve Irganox 1010 on low density polyethylene (LDPE) was used because the collision cascade takes place completely in organic material (simulation of "real" polymer conditions), the analyte of interest is only present in the uppermost monolayer (no contribution from deeper layers) and shows characteristic secondary ions covering the complete mass range from 1-1000u whereas the aliphatic substrate polymer LDPE emits ions only in the low mass range. The secondary ion parameters yield Y, disappearance cross-section @sigma@ and secondary ion emission efficiency E (yield per damaged area) were determined for primary ion bombardment with several monoatomic as well as polyatomic primary ions including Ga@super +@, Cs@super +@, Au@super +@ as well as SF@sub 5@@super +@, Au@sub 2@@super +@ and Au@sub 3@@super +@. Additionally, the primary ion energies were varied between 4 and 25 keV. The results can be summarized as follows: For monoatomic primary ion bombardment the efficiency increases with the primary ion mass. Maximum enhancement factors compared to Ga@super +@ bombardment are about 5-10. Polyatomic primary ion bombardment leads to enhancement factors of at least 60. Optimum primary ion energies depend on the respective ion species. These results have consequences for the achievable lateral resolution in ion imaging as well as for the detection limits in surface spectrometry. Examples will be given.