摘要:
A surface acoustic wave device includes a substrate including lithium niobate; a IDT being provided on an upper surface of the substrate and including a plurality of electrode fingers; and a protective film covering the IDT and having an uneven shape on an upper surface thereof. When a pitch width of one pitch of the IDT is p, a width of one of the electrode fingers is p1, a width between the electrode fingers is p2, and a thickness of the IDT is h, following relations are satisfied, p1+p2=p, and h/(2×p)≧4.5%. With this configuration, an appropriate reflection characteristic is realized, and the surface acoustic wave device having excellent temperature coefficient of frequency and electrical characteristic can be obtained.
摘要:
A surface acoustic wave device includes a substrate including lithium niobate; a IDT being provided on an upper surface of the substrate and including a plurality of electrode fingers; and a protective film covering the IDT and having an uneven shape on an upper surface thereof. When a pitch width of one pitch of the IDT is p, a width of one of the electrode fingers is p1, a width between the electrode fingers is p2, and a thickness of the IDT is h, following relations are satisfied, p1+p2=p, and h/(2×p)≧4.5%. With this configuration, an appropriate reflection characteristic is realized, and the surface acoustic wave device having excellent temperature coefficient of frequency and electrical characteristic can be obtained.
摘要:
A plurality of surface acoustic wave resonators including a comb electrode and a grating reflector are coupled on a piezoelectric substrate. Dielectric film is formed on the surface of at least one surface acoustic wave resonator. No dielectric film is formed on the surface of at least one other surface acoustic wave resonator. Thus, a SAW filter where the insertion loss into a pass band is small, the steepness is sufficient, and the band is wide can be obtained.
摘要:
An electronic part, an object of which is to improve temperature characteristics and electrical properties, includes a substrate (1), a comb-type electrode (2) that is disposed on the upper surface of the substrate (1), and a protective film (4) that covers the comb-type electrode (2) and has an uneven shape at its top surface. If the pitch width of one pitch in the uneven shape of the protective film (4) is L, the width of one pitch of a convex portion (4a) of the unevenness in the uneven shape of the protective film (4) is L1, the width of one pitch of a concave portion (4b) thereof is L2, the pitch width of one pitch of the comb-type electrode (2) is p, the width of one of electrode fingers which form the comb-type electrode (2) is p1 and the width between the electrode fingers is p2, then each parameter is set so that the following expressions are satisfied, L1≦p1 and L2≧p2 (herein, the correlations of L≈p, p1+p2=p and L1+L2=L are satisfied).
摘要:
In a surface acoustic wave (SAW) filter including a substrate and an electrode formed on the substrate, the electrode includes a base layer, a first metal layer made of a metal consisting of Al or consisting mainly of Al, and having a given orientation relative to the substrate, a second layer for preventing the first metal layer from migration of Al atoms occurring in vertical to the substrate, and a third layer for adjusting a thickness of the layer. In this SAW filter having an arbitrary layer thickness, the layer hardly causes grain boundary diffusion, and grains of the layer can be made fine for effective resistance to stress. Thus, in this SAW filter, the migration of the Al atoms of the electrode that is associated with the SAW propagation-induced stress imposed on the electrode is inhibited. Accordingly, the filter exhibits excellent resistance against electric power.
摘要:
In a surface acoustic wave (SAW) device, such as a SAW resonator or a SAW filter, loss is minimized and steep characteristics are improved. IDT electrodes and a reflector are provided to a piezoelectric substrate cut out at a cut-angle which allows the substrate to excite a leaky surface acoustic wave (LSAW). The IDT electrodes have a given film thickness and a given pitch “p” of finger-electrodes. A phase velocity of the SAW is reduced to slower than a phase velocity “vb”of a slow shear wave propagating on the piezoelectric substrate, and a resonance frequency “f” satisfies a relation of 2×p≦vb/f. This structure allows the use of a Rayleigh surface acoustic wave (RSAW) which does not produce propagation loss, and improving insertion-loss and steep characteristics from those of a conventional SAW device using the LSAW.
摘要:
In a piezoelectric element 20, a first electrode layer 2 made of an alloy of at least one metal selected from the group consisting of cobalt, nickel, iron, manganese and copper and a noble metal is formed on a silicon substrate 1, and a piezoelectric layer 3 made of a rhombohedral or tetragonal perovskite oxide (e.g., PZT) is formed on the first electrode layer 2 so that the piezoelectric layer 3 is preferentially oriented along the (001) plane.
摘要:
In a piezoelectric element, an adhesive layer 12 is provided on a substrate 11, a first electrode layer 14 made of a noble metal containing titanium or titanium oxide is provided on the adhesive layer 12, and an orientation control layer 15 that is preferentially oriented along a (100) or (001) plane is provided on the first electrode layer 14. In the vicinity of a surface of the orientation control layer 15 that is closer to the first electrode layer 14, a (100)- or (001)-oriented region extends over titanium or titanium oxide located on one surface of the first electrode layer 14 that is closer to the orientation control layer 15, and the cross-sectional area of the region in the direction perpendicular to the thickness direction gradually increases in the direction away from the first electrode layer 14 toward the opposite side. Further, a piezoelectric layer 16 that is preferentially oriented along a (001) plane is provided on the orientation control layer 15.
摘要:
A first electrode layer made of a noble metal containing at least one additive selected from the group consisting of Ti, Co, Ni, Mg, Fe, Ca, Sr, Mn, Ba and Al and oxides thereof, a pyroelectric layer having a thickness of 0.5 to 5 μm and having a perovskite crystalline structure whose chemical composition is represented as (Pb(1-y)Lay)Ti(1-y/4)O3 (0
摘要:
A method for fabricating a dielectric device including a capacitor, a pyroelectric infrared detector, and the like is disclosed. The method comprises the steps of etching a dielectric substance film formed on a substrate to form a predetermined pattern with an etchant comprised of hydrofluoric acid and an oxidizing agent, and removing residues resulting from the etching by treating the etched layer with a first treating solution containing a reducing agent and subsequently with a second treating solution containing an acid.