The interaction of a 75J 10ps, high intensity laser beam with low-mass, solid Cu targets is investigated. Two instruments were fielded as diagnostics of Cu K-shell emission from the targets: a single photon counting spectrometer provided the absolute Kα yield [C. Stoeckl et al., Rev. Sci. Instrum. 75, 3705 (2004)] and a spherically bent Bragg crystal recorded 2D monochromatic images with a spatial resolution of 10μm [J. A. Koch et al., Rev. Sci. Instrum. 74, 2130 (2003)]. Due to the shifting and broadening of the Kα spectral lines with increasing temperature, there is a temperature dependence of the crystal collection efficiency. This affects measurements of the spatial pattern of electron transport, and it provides a temperature diagnostic when cross calibrated against the single photon counting spectrometer. The experimental data showing changing collection efficiency are presented. The results are discussed in light of modeling of the temperature-dependent spectrum of Cu K-shell emission.

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Hexagonal aluminium nitride (AlN) thin films prepared by the reactive magnetron sputtering method usually undergo post-growth annealing treatment aimed at the improvement of crystalline quality as a principal step for their performance as piezoelectric transducers in micro-electro-mechanical systems. Herein, the post-growth annealing of AlN films deposited on Si (111) is investigated by Raman and Fourier transform infrared spectroscopies, X-ray diffraction, and scanning probe microscopies. The thermally treated films show a positive trend in stress relaxation via annealing up to 1200 C; however, it is accompanied by a dewetting of the quasi-epitaxial layer and the formation of the cubic AlN phase. The critical role is played by the AlN/Si interface being sensitive to oxidation via interstitial oxygen in Si wafers. The piezoelectric performance of the AlN/Si system is found to be inversely proportional to the post-growth annealing temperature.

A 2D scanning micromirror with piezoelectric thin film aluminum nitride (AlN), separately used as actuator and sensor material, is presented. For endoscopic applications, such as fluorescence microscopy, the devices have a mirror plate diameter of 0.7 mm with a 4 mm2 chip footprint. After an initial design optimization procedure, two micromirror designs were realized. Different spring parameters for x- and y-tilt were chosen to generate spiral (Design 1) or Lissajous (Design 2) scan patterns. An additional layout, with integrated tilt angle sensors, was introduced (Design 1-S) to enable a closed-loop control. The micromirror devices were monolithically fabricated in 150 mm silicon-on-insulator (SOI) technology. Si (111) was used as the device silicon layer to support a high C-axis oriented growth of AlN. The fabricated micromirror devices were characterized in terms of their scanning and sensor characteristics in air. A scan angle of 91.2° was reached for Design 1 at 13 834 Hz and 50 V. For Design 2 a scan angle of 92.4° at 12 060 Hz, and 123.9° at 13 145 Hz, was reached at 50 V for the x- and y-axis, respectively. The desired 2D scan patterns were successfully generated. A sensor angle sensitivity of 1.9 pC/° was achieved.

Pulsed DC magnetron sputtered aluminum nitride (AlN) thin films are prepared on several seed layers and at different sputtering conditions. The piezoelectric c-axis (002) orientation of the AlN is analyzed with X-ray diffraction method. The transverse piezoelectric coefficient d31 is determined with a Laser-Doppler-Vibrometer at cantilevers and membranes by analytical calculations and finite element method. Additionally, thin film AlN on bulk silicon is used to characterize the longitudinal piezoelectric charge coefficient d33.

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In this work, aluminium scandium nitride ($$\hbox {Al}_{1-x}\hbox {Sc}_{x}\hbox {N}$$ Al 1 - x Sc x N ) thin films are deposited by reactive DC magnetron co-sputtering on Pt(111) layers. The sputtering power of the Sc target is varied in a broad range up to 900 W to effectively vary the Sc content later assessed using energy-dispersive X-ray spectroscopy (EDX). We show that commonly used X-ray diffraction techniques may yield ambiguous results, and thus, additional verification is crucial to substantiate the actual composition of the sputtered thin films. Therefore, we employ optical spectroscopy techniques, such as Raman and Fourier transformed infra-red (FTIR) spectroscopies in order to study the vibrational properties of the alloys. Our Raman spectra show that low Sc content leads to a phase separation with the formation of cubic ScN and AlScN phases during the sputtering process. Nevertheless, small amounts of the wurtzite phase are detected in the rock-salt dominated samples owing to the enhancement of the $$\hbox {A}_{{1}}$$ A 1 (LO) phonon mode by the Berreman effect in the FTIR spectra. The Sc-induced shifts of the AlN phonon modes are determined in a broad range of Sc content.

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