Photoluminescence-based detection of particle contamination on extreme ultraviolet reticles.

Here, we propose a comparison-free inspection technique to detect particle contamination on the reticle of extreme ultraviolet (EUV) lithography systems, based on the photoluminescence spectral characteristics of the contaminant particles and their elemental composition. We have analyzed the spectra from different particles found on reticles in EUV lithographic systems and have determined the minimum detectable particle size: 25 nm for organic particles and 100 nm for Al particles. Stainless steel coatings (50 nm thick and 50 × 50 µm(2) in area) exhibit detectable photoluminescence, and the estimated minimum detectable particle is 2 µm.

Compact cryogenic Kerr microscope for time-resolved studies of electron spin transport in microstructures.

A compact cryogenic Kerr microscope for operation in the small volume of high-field magnets is described. It is suited for measurements both in Voigt and Faraday configurations. Coupled with a pulsed laser source, the microscope is used to measure the time-resolved Kerr rotation response of semiconductor microstructures with approximately 1 mum spatial resolution. The microscope was designed to study spin transport, a critical issue in the field of spintronics. It is thus possible to generate spin polarization at a given location on a microstructure and probe it at a different location. The operation of the microscope is demonstrated by time-resolved measurements of micrometer distance diffusion of spin polarized electrons in a GaAs/AlGaAs heterojunction quantum well at 4.2 K and 7 T.

Charge and spin dynamics in a two-dimensional electron gas.

A number of time-resolved optical experiments probing and controlling the spin and charge dynamics of the high-mobility two-dimensional electron gas in a GaAs/AlGaAs heterojunction are discussed. These include time-resolved reflectivity, luminescence, transient grating, magneto-optical Kerr effect, and electro-optical Kerr effect experiments. The optical experiments provide information on the carrier lifetimes and spin dephasing times, as well as on the carrier diffusion coefficient which directly gives the charge mobility. A combination of the two types of Kerr experiment proves to be useful in extracting both the carrier lifetimes and spin dephasing times in a single experiment.