Time-resolved spectroscopy of solid-state materials using an EUV laser

Sarukura, Nobuhiko*; Furukawa, Yusuke*; Murakami, Hidetoshi*; Saito, Shigeki*; Nishimura, Hiroaki*; Mima, Kunioki*; Tanaka, Momoko; Nishikino, Masaharu; Yamatani, Hiroshi; Nagashima, Keisuke; Kimura, Toyoaki; Kagamitani, Yuji*; Fukuda, Tsuguo*

Optical technologies in the extreme ultraviolet (EUV) region have been receiving strong interest for the next generation lithography. Here we report properties of ZnO and GaN as scintillators in the EUV region, and to demonstrate the feasibility of using a Ni-like Ag EUV laser operated at 13.9-nm to evaluate these properties. The sample was irradiated with EUV laser pulses and the fluorescence were measured using a streak camera fitted with a spectrograph. In the case of ZnO, a clear, excitonic, fluorescence peak was observed at around 380 nm with a decay lifetime of 3 ns, as shown in Fig. 1. The prominent peak fluorescence is ideal for EUV detection and further applications including imaging. For GaN, a fluorescence peak at 370 nm having slower 5-ns decay time was observed. In this respect, the EUV scintillation properties of ZnO is said to be more favorable than GaN.