Highly repetitive, extreme-ultraviolet radiation source based on a gas-discharge plasma.
An extreme-ultraviolet (EUV) radiation source near the 13-nm wavelength generated in a small (1.1 J) pinch plasma is presented. The ignition of the plasma occurs in a pseudosparklike electrode geometry, which allows for omitting a switch between the storage capacity and the electrode system and for low inductive coupling of the electrically stored energy to the plasma. Thus 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 temperatures of several tens of electron volts, which is necessary for emission in the EUV range. As an example, the emission spectrum of an oxygen plasma in the 11-18-nm range is presented. Transitions of beryllium- and lithium-like oxygen ions can be identified. Current waveform and time-resolved measurements of the EUV emission are discussed. In initial experiments a repetitive operation at nearly 0.2 kHz could be demonstrated. Additionally, the broadband emission of a xenon plasma generated in a 2.2-J discharge is presented.
Bergmann
K
K
Lehrstuhl für Lasertechnik, Rheinisch-Westfälische Technische Hochschule Aachen, Steinbachstrasse 15, D-52074 Aachen, Germany. k_bergmann@ilt.fhg.de
Schriever
G
G
Rosier
O
O
Müller
M
M
Neff
W
W
Lebert
R
R