Irradiation stability of silicon photodiodes for extreme-ultraviolet radiation

Abstract

Photodiodes are used as easy-to-operate detectors in the extreme-ultraviolet spectral range. At the Physikalisch-Technische Bundesanstalt photodiodes are calibrated with an uncertainty of spectral responsivity of 0.3% or less. Stable photodiodes are a prerequisite for the dissemination of these high-accuracy calibrations to customers. Silicon photodiodes with different top layers were exposed to intense extreme-ultraviolet irradiation. Diodes coated with diamondlike carbon or TiSiN proved to be stable within a few percent up to a radiant exposure of 100 kJ/cm2. The changes in responsivity could be explained as being due to carbon contamination and to changes in the internal charge collection efficiency. In ultrahigh vacuum, no indication of oxidation was found.

A close look at dose: Toward L-edge XAS spectral uniformity, dose quantification and prediction of metal ion photoreduction

“…While for example AXUV and SXUV diodes can be calibrated against the SYRES spectrometer at the physikalisch-technische bundesanstalt (PTB) in Berlin to allow for an error of <0.3% [108][109][110], there are few beamlines that have such calibrated diodes available. Moreover, diode temperature [111], diode surface coverage [112], the position and size of the beam on the diode [113] and the maximum flux such diodes can handle [112] limit their lifetimes significantly and introduces large errors in absolute flux quantification. Additional errors are expected to result from the use of gold meshes instead of calibrated diodes.…”

Linearity tests of silicon photodiodes for EUV radiation

“…For all other apertures, an appropriate signal was available. It was shown previously that the special SXUV type diodes used here are stable for irradiation under UHV-atmosphere up to 150 kJ/cm 2 [10]. So because the measurements at the highest flux presented here took only a few minutes, effects of diode damage should not be observed in the measurements.…”

The EUV metrology program of PTB

“…5 shows the influence of the EUV irradiation of a SXUV photodiode in ''good vacuum'' on the spectral responsivity. It can be seen that even after a time integrated irradiance of 143 kJ/cm 2 , the spectral responsivity stays stable for that type of photodiode [13].…”