Effect of substrate composition on the piezoelectric response of reactively sputtered AlN thin films

Energy Saving Melting and Revert Reduction Technology (E-SMARRT): Development of Surface Engineered Coating Systems for Aluminum Pressure Die Casting Dies: Towards a 'Smart' Die Coating

“…The Al atoms and N atoms are placed on alternate planes in a hexagonal array as shown in Figure 7 [34]. The ultimate piezoelectric activity in this material is found to be restricted to the perpendicular direction to the hexagonal arrays or (002) orientation, also known as the 'c'-axis [35,36]. It also happens to be the natural (thermodynamically/energetically stable) growth direction of a thin film.…”

Low-thickness high-quality aluminum nitride films for super high frequency solidly mounted resonators

“…The power of this pre-deposition bombardment had to be carefully tuned, as too low values (30 W) yielded poorly textured AIN films (wide RCs), whereas too high values (200 W) produced AIN films with low etch-ability in hot phosphoric solutions, which has been associated to the formation of inverted domains [24,25]. Thus, the overall pre-treatment of the surface acted in two different ways; firstly by modifying the state of the Ir surface (removing contaminants) and secondly by homogenizing the activation state of the surface to promote the growth of AIN grains with a single polar orientation.…”

X-Ray Analysis on Ceramic Materials Deposited by Sputtering and Reactive Sputtering for Sensing Applications

“…Aluminum nitride is a semiconductor of the III-V semiconductor group, with an hexagonal wurtzite crystalline structure (Penza et al, 1995;Xu et al, 2001), lattice constants of a = 0.3110 nm e c =0.4980 nm (Xu et al, 2001), and is characterized by a broad direct energy gap (6.2 eV) (Cheng et al, 2003;Hirata et al, 2007;Penza et al, 1995), chemical stability (Cheng et al, 2003;Penza et al, 1995), high thermal conductivity (3.2 W/mK) (Cheng et al, 2003), low thermal expansion coefficient (4.5 ppm/°C) (Ruffner et al, 1999), high breakdown voltage (Hirata et al, 2007;Xu et al, 2001), high acoustic speed (Cheng et al, 2003;Xu et al, 2001), high refractive index (n = 2.1) (Penza et al, 1995), high electrical resistivity (10 11 -10 14 cm) (Ruffner et al, 1999) and, above all, good piezoelectric response (Cheng et al, 2003;Hirata et al, 2007;Penza et al, 1995;Ruffner et al, 1999;Xu et al, 2001) (piezoelectric coefficient of 5.4 pm/V) (Ruffner et al, 1999). Piezoelectric behaviour of AlN strongly depends on its crystallographic orientation (Cheng et al, 2003) and, in particular, films grown in the [002] orientation are preferred as the highest www.intechopen.com…”