Pulse-extended excimer laser annealing of lead zirconate titanate thin films

Excimer laser annealing is a promising method for the crystallisation of fe rroelectric layers, such as PZT, in low thermal budget integrated device fa brication processes. A technique is described whereby the problem of very h igh surface temperatures in PZT is overcome by the use of temporal pulse ex tension, where the effective laser pulse length is increased from 24ns to 3 74ns. Modelled temperature profiles through a PZT thin film structure durin g laser irradiation illustrate the benefit of pulse extension due to enhanc ed heat propagation into the PZT. The modelling also shows that underlying silicon is not heated significantly even with pulse extension. Initial resu lts show that PZT can be crystallised into the perovskite phase from the to p downwards with minimal surface damage.