Ion bombardment-induced high orientation of Al/Ti films for surface acoustic wave device applications

Abstract

Al/Ti films were deposited on 128°Y-X LiNbO 3 substrates by electron-beam (e-beam) deposition. Low-energy Ar ion beam bombardment was employed during the Ti underlayer deposition. Influence of low-energy beam bombardment on the texture of Al/Ti films was investigated by x-ray diffraction (XRD) analysis. It was found that Al films deposited on Ar-ion bombarded Ti underlayers possessed excellent (111) texture. With the textured Al/Ti films, a 2.3-GHz range image-impedance connection surface acoustic wave (SAW) filter was successfully fabricated.

Improvement in Power Durability of Al Electrode Films Used in SAW Devices by Zr Additive and Ti Underlayer

“…We obtained highly textured Al (111) films on a Ti underlayer using the IBAD technique. 8 In the present case, the Al (111) orientation of the Al-Zr alloys on the Ti underlayer was improved using the sputtering technique by controlling the sputtering pressure. Figure 6 shows the effect of the orientation of the Al-0.2%(wt.%)Zr/Ti electrode film on lifetime.…”

“…6,7 The ion-beam-assisted deposition (IBAD) technique was employed to improve the crystallinity of Al and the mechanical properties of Al/Ti bilayered films. 8,9 In this paper, both Zr-doped Al and a Ti underlayer were deposited by radiofrequency (RF) sputtering on ferroelectric 128°Y-X LiNbO 3 substrates, which were expected to increase the power durability of Al electrode films and obtain fine-dimensional control. The effect of microstructure and Zr addition on the failure time, residual stress, and electrical resistivity of the Al-Zr/Ti bilayered films was investigated to improve durability.…”

Improved electromigration reliability of surface acoustic wave devices using Ti/Al-Mo/Ti/Al-Mo electrodes

“…Many factors are known to influence thin-film texture evolution through nucleation, growth, substrate material, lattice matching between film and substrate, growth condition, deposition technique, surface morphology of substrate, etc. Low-energy ion bombardment can effectively improve the texture of the films deposited on Ti underlayer [11][12]. In addition, it is reported that Al films deposited on the amorphous layer, which has high surface free energy, show strong (111) texture [13].…”

“…Comparatively, as seen in Table 1, Mo and Ti as additive elements are more compatible with dry etching using chlorinated gases because of the low boiling temperature of MoCl 5 and TiCl 4 . On the other hand, it is reported that a layer such as a combination of Al and a refractory metal might provide high reliability and adhesion to the substrates [11]. Therefore, a new 4-layered Ti/Al-Mo/Ti/Al-Mo electrode was developed in this paper.…”