Сравнительное исследование термостойкости пелликлов на основе бериллия

We demonstrate the possibility of manufacturing Be-based ultrathin films with high transmission at wavelengths of 11.4 and 13.5 nm. For free-standing films of Be and Be-based multilayer structures (Si/Be, ZrSi2/Be, Be/BexNy, Zr/Be, Ru/Be, Mo/Be), we determine the thresholds of the absorbed power at which over a short period (tens of minutes) of vacuum annealing, initially sagging free-standing films became visibly stretched over the hole. Of the film structures tested here, the Be/BexNy structure (with beryllium nitride interlayers) showed the highest threshold for the absorbed power (1 W/cm2). However, due to the low strength of this structure, ZrSi2/Be, Mo/Be, and Be films seem to be more promising for the manufacture of a full-size pellicle. Long-term vacuum annealing of Mo/Be and Be ultrathin films showed that they could withstand 24 hours of vacuum heating at an absorbed power density of 0.2 W/cm2 (film temperature ~250°C) without noticeable changes in EUV transmission or sagging of films. With comparable transmission (~83% at 13.5 nm and ~88% at 11.4 nm), a multilayer Mo/Be structure with a thickness of 30 nm appears to be preferable, as it shows less brittleness than a monolayer Be film with a thickness of 50 nm.

Transformation of CaSi overgrowth domains to the CaSi2 crystal phase via vacuum annealing

The phase transformation of overgrown CaSi crystal on an (00l)-oriented epitaxial CaSi2 film was studied using high-angle annular dark-field scanning transmission electron microscopy. After annealing at 450°C under vacuum conditions, the CaSi domain transformed to the CaSi2 phase with thin Si layers. The transformed CaSi2 crystal formed epitaxially along the under-layer epitaxial CaSi2 film. The results suggest that Ca atoms in the overgrown CaSi domain diffused to the outermost passivated silicon oxide layer during the low-temperature vacuum anneal.

Annealing effect of absorber layer on SnS/CdS heterojunction band alignments

The effect of annealing on physical properties of a SnS thin film and also on SnS/CdS heterojunction band alignment was studied. Vacuum annealing has greatly improved the crystalline quality of SnS and average grain size of 1.6 µm was achieved. Sulfur-rich secondary phases observed on the surface of as-grown SnS thin film were eliminated after vacuum annealing, resulting in a decrease of the resistivity and an increase of the carrier concentration of the film. A maximum hole mobility of 17 cm2V-1s-1 was obtained for SnS thin films annealed at 400 ֯C. A transition of SnS/CdS heterojunction from “spike” type to “cliff” type was observed when the vacuum annealed SnS thin film was post-air-annealed at 200 and 250 ֯C. The band alignment of SnS/CdS heterojunction could be adjustable between “spike” type to “cliff” type via vacuum annealing followed by post-air-annealing.