New Design and Development of Size-Selected Gas Cluster SIMS

作者：Moritani Kousuke^*; Hashinokuchi Michihiro; Mukai Gen; Mochiji Kozo

来源：Electrical Engineering in Japan, 2011, 176(3): 52-58.

DOI：10.1002/eej.21159

• TOF-SIMS
• gas cluster ion beam
• surface analysis
• polymer

A new cluster time-of-flight secondary ion mass spectrometry (TOF-SIMS) was developed, using a size-selected gas cluster ion as a projectile. Because a large gas cluster ion can generate numerous low-energy constituent atoms during a collision with the surface, multiple and ultralow-energy sputterings are induced. Dividing the acceleration energy of a gas cluster ion by the number of constituent atoms provides the mean kinetic energy of the constituent atoms. Hence, sputtering can be controlled to minimize decomposition of the sample molecules by precisely adjusting the number of constituent atoms (the cluster size) and/or the acceleration energy of the gas cluster ions. The cluster size was selected by the time-of-flight method using two ion deflectors attached along the ion-beam line. A high resolution of 11.7 was achieved for the cluster size/size width (m/Delta m) of the Ar-cluster ions. The SIM spectra of poly(methyl methacrylate) (PMMA) were measured using the size-selected gas-cluster SIMS machine. The large fragment ions emitted from PMMA are enhanced as the cluster size increases. This result suggests that a large cluster ion projectile in which each constituent atom within the cluster has decreased kinetic energy inhibits the decomposition of the polymer structure.

• 出版日期2011-8