Characterisation of compact discs using time of flight-energy elastic recoil detection analysis

The challenge of meeting the ever increasing demands for low-cost informati on storage media with greater information storage density and rapid access has prompted development of sophisticated optical technologies, e.g., compa ct disc (CD) and digital video disc (DVD) in read only memory (ROM), record able (R), rewritable (RW) and random access memory (RAM). Here the suitabil ity of time of flight-energy elastic recoil detection analysis (ToF-E ERDA) to characterise optical storage media film has been investigated. High-ene rgy heavy ions (48 MeV Br-81(8+) and 60 MeV I-127(10+)) from a tandem accel erator were used to analyse CD-ROM, CD-R and CD-RW structures. Up to 9 elem ents, H, C, O Al, P, Co, Cr, Ge, and Sb/Te could be distinguished simultane ously. The results demonstrate the unique power of the technique for charac terising the composition and depth profile of the optical multi-layers as w ell as the ingress and influence of foreign species.