Highly repetitive, extreme-ultraviolet radiation source based on a gas-discharge plasma

An extreme-ultraviolet (EUV) radiation source near the 13-nm wavelength gen erated in a small (1.1 J) pinch plasma is presented. The ignition of the pl asma occurs in a pseudosparklike electrode geometry, which allows for omitt ing a switch between the storage capacity and the electrode system and for low inductive coupling of the electrically stored energy to the plasma. Thu s energies of only a few joules are sufficient to create current pulses in the range of several kiloamperes, which lead to a compression and a heating of the plasmas to electron densities of more than 10(17) cm(-3) and temper atures of several tens of electron volts, which is necessary for emission i n the EUV range. As an example, the emission spectrum of an oxygen plasma i n the 11-18-nm range is presented. Transitions of beryllium- and lithium-li ke oxygen ions can be identified. Current waveform and time-resolved measur ements of the EUV emission are discussed. In initial experiments a repetiti ve operation at nearly 0.2 kHz could be demonstrated. Additionally, the bro adband emission of a xenon plasma generated in a 2.2-J discharge is present ed. (C) 1999 Optical Society of America.