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We report on the properties of Aluminum Scandium Nitride (AlScN) thin films deposited by pulsed-DC co-sputtering. We present the impact of the nitrogen-to-argon gas ratio on the crystal growth orientation, film stress, surface roughness, scandium concentration, and deposition rate of 760-860 nm thick AlScN thin films on Ti/Pt (111). We utilize the optimized process conditions from this study to deposit thin layers of AlScN and to explore the nucleation and orientation of thin AlScN layers on Ti/Pt (111). We report on the ferroelectric properties of 100 nm thick AlScN materials.

The discovery of enhanced piezoelectricity in solid solutions of AlN and ScN is certainly one of the most important events in piezoelectric MEMS. As compared to pure AlN, it brought a crucial factor 2 to 3 improvement in a number of figures of merit governing the performance of MEMS devices. The aim of this contribution is to give a short overview on actual topics in processing, properties, and applications in RF filters and sensors.

The enhancement of the electromechanical coupling coefficient caused by Sc substitution in AlN-based piezoelectric MEMS devices can be exploited successfully only if the dielectric losses remain confined to low values. While the magnitude of the piezoelectric activity in Al 1-x Sc x N thin films has been described widely in the literature, the impact of the Sc content on the loss tangent has not been studied extensively. In this work we discuss the dissipation factor obtained for x=0.095 and x=0.3 on Mo and Pt bottom electrodes, for full capacitor stacks deposited with an EVATEC Clusterline®200–II PVD tool equipped with single alloy targets 304mm in diameter.

Aluminium scandium nitride (ASN) exhibits a largely enhanced piezoelectric response as compared to aluminium nitride (AlN), which makes it an upcoming piezoelectric material for use in next generation RF filters, sensors, actuators and energy harvesting devices. In this work, process-microstructure-property relationships of such sputtered ASN films containing up to 42 at% Sc were investigated. Hereby, the influence of the process parameters on the film structure, the intrinsic stress and the piezoelectric response were carefully investigated. A high piezoelectric response (e(31),(f) = -2.67 C/m(2) and d(33,f) = 10.3 pm/V) was measured for films with 42 at% and 34 at% Sc, respectively. The results are very promising towards industrial applications.

Recent literature has focused on improving piezoelectric coupling coefficients by alloying aluminum nitride (AlN) with scandium (Sc). Akiyama et al. showed the highest d_33 piezoelectric coefficient increase of >4x at a 41% Sc substitution for Al. Thus far, studies mainly focus on material measurements such as x-ray diffraction or piezoelectric constants to assess the material quality. Although these measurements are useful to assess the improvement in the piezoelectric performance of the material, they do not address improvements in the figure-of-merit (FOM) of resonators (i.e., coupling coefficient times quality factor). Resonator structures are needed to directly extract these key performance parameters for film assessment. Fabrication integration, however, must be minimized to avoid obscuring film performance by extrinsic device effects.

Recent literature has focused on improving piezoelectric coupling coefficients by alloying aluminum nitride (AlN) with scandium (Sc). Akiyama et al. showed the highest piezoelectric coefficient increase of nearly four times for a 41% Sc substitution for Al. Thus far, studies mainly focus on material measurements such as x-ray diffraction or piezoelectric constants to assess the material quality. Although these measurements are useful to assess the improvement in the piezoelectric performance of the material, they do not address changes in the coupling coefficient and quality factor. Resonator structures are needed to directly extract these key performance parameters for film assessment. Fabrication integration, however, must be minimized to avoid obscuring film performance by extrinsic device effects. In this work, we assess a film evaluation tool using contour mode resonators (CMRs) to directly extract resonator performance for film comparison. Resonators formed from AlN, Sc 0.06 Al 0.94 N, and Sc 0.125 Al 0.875 N films are compared to demonstrate the method.

Aluminium scandium nitride (Al 1−x Sc x N) with its strongly enhanced piezoelectric response is the upcoming piezoelectric material of choice in next generation RF filters, sensors, actuators and energy harvesting devices. This paper will concentrate on the deposition technology for Al 1−x Sc x N films with high Sc content. Films with Sc concentrations close to 43 at% have been grown on 200-mm substrates using a cluster type sputter deposition tool. The piezoelectric response will be discussed and correlated with the deposition parameters and film structural properties. The steps required to deliver a high-volume production solution for high Sc concentration will be described.

Organic passivated silicon wafers, composite substrates such as silicon on glass or Fan-out Wafer-Level Package (FOWLP) technology all pose new challenges for UBM and RDL processes [1]-[5]. Materials used in these substrates must be adequately degassed for subsequent plasma processing under vacuum but their heat-sensitive nature necessitates careful thermal management. Selecting the proper technology for each individual step enables the definition of a high yield process, minimizing contamination from the organic materials. This paper discusses the preferred degas principles for different substrates and applications. Temperature simulation data and experimental results are presented for various heating methods including single wafer and batch processes. It illustrates the effectiveness of an atmospheric batch degasser for removal of volatile water and organic compounds (VC) at moderate temperatures below 150°C. The results will be compared with standard vacuum degas technologies and the resulting contact resistance (Rc) values after subsequent low temperature ICP etch will be reported. The paper also addresses the etch process requirements to ensure efficient pumping of remaining volatile contaminants, the required temperature management of the substrates and the particle containment and cleanliness of the process environment.

In the present study, high quality PZT films were deposited by RF magnetron sputtering onto 200mm thermally oxidized silicon substrates at substrate holder temperatures (T h ) between 550°C – 700°C using PbO-enriched single ceramic PZT targets. The high substrate temperatures used here allowed direct growth of the piezoelectric perovskite phase and rendered an additional post annealing step unnecessary. The PZT layers were grown on (111) oriented Pt bottom electrodes, which were covered by thin TiO 2 seed layers. Over the temperature range investigated here, there was a monotonic reduction in the Pb/(Zr+Ti) atomic ratio with increasing Th; the stoichiometry of the morphotropic phase boundary Pb/(Zr+Ti) ∼ 1 and Zr/(Zr+Ti) ∼ 0.53 was obtained at 700°C. However, the XRD patterns indicated that the films prepared at intermediate T h = 600°C exhibited the minimum volume fraction of the spurious pyrochlore phase in addition to tetragonal and rhombohedral piezoelectric PZT structures. All PZT films contained mixed (110), (111) and (200) crystallographic orientations whose relative intensities were significantly influenced by T h . The highest piezoelectric coefficients d 33,f = 120 pm/V and e 31,f = −12.6 C/m2 were obtained for the films deposited at T h = 600°C.

Ferroelectric PZT thin films have been in-situ deposited on 8-inch wafers by a high volume production sputtering tool. The films were grown on oxidized Si substrates covered either with sputtered Ti/TiO 2 /Pt, sputtered Ti/TiO 2 /Pt/TiO 2 or evaporated Ti/Pt bottom electrodes and investigated with respect to their chemical composition, crystallographic and dielectric properties. Moreover the d 33,f and the e 31,f coefficients have been examined. At a chuck temperature of 600 °C the intended chemical composition is achieved to nucleate and grow the ferroelectric perovskite phase with a minimum of secondary non-piezoelectric phases. A Zr/(Zr+Ti) ratio of 0.53 has been achieved matching to the morphotropic phase boundary. Notable high e 31,f and d 33,f coefficients of 101 pm/V and −13.8 C/m2, respectively, have been obtained

A spin coating technique for the 100 micron cover layer for Blu-Ray Disc production has been developed. The process includes a controlled manipulation of the viscosity of the lacquer with heat and UV light during spin coating. Stability and cost efficiency, two vital criteria for mass production, have been considered. Keywords: Optical Storage, Spin Coating, Blu-Ray Disc 1. INTRODUCTION With the Blu-Ray Disc, the 3rd generation of optical storage media is today appearing on the consumer market. While moulding and sputtering processes for substrate preparation and functional layer application are very similar to the currently used processes for CD and DVD production, the reliable and cost efficient application of a highly precise, 100 P m thick optical layer on top of the information layer is the challenging production step for this format. Since the very beginning of the Blu-Ray Disc, there have been two techniques discussed between media developers, equipment manufacturers, consumables suppliers and media producers for the 100 P m cover layer production: Spin coating of a UV curable resin is seen as one candidate, bonding a cover layer sheet stands as the alternative. Looking at the foil bonding technology one has to distinguish between PSA-sheet bonding and UV-resin bonding of a thin polycarbonate sheet. The PSA sheet bonding is a proven method which gives excellent cover layer thickness homogeneity. The PSA adhesive is supplied together with the foil and the manufacturing process of the disc is relatively simple. But due to the high cost per sheet it can only be seen as a start-up technology for the Blu-Ray Disc media family. It is not seen as an attractive solution for economic mass production because the cost per sheet cannot be reduced significantly. The foil bonding technology using UV-resin combines a spinning process and a bonding process similar to standard DVD bonding technology. A UV-curable resin is applied onto the BD substrate, spread over the disc in a spin coating process and combined with the foil, preferably in a vacuum bonding process, and finally the system is cured under UV irradiation. Like PSA-sheet bonding, foil bonding technology us ing UV-resin is a practical way to go. In both cases it is the quality of the foil which significantly de termines the quality of the cover layer. Using a spin coating process